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Advantages of reaction cell ICP-MS on doubly charged interferences for arsenic and selenium analysis in foods
Abstract
Recent reports of As concentrations in certain food and drinks has garnered public concern and led to a lowering of the US guideline maximum concentration for inorganic As in apple juice and proposed limits for As in rice products. In contrast Se is an essential micro-nutrient that can be limiting when Se-poor soils yield Se-poor food crops. Rare earth element (REE) doubly charged interferences on As and Se can be significant even when initial ICP-MS tuning minimizes doubly charged formation. We analyzed NIST 1547 (peach leaves) and 1515 (apple leaves), which contain high levels of REEs, by quadrupole ICP-MS with (He) collision mode, H2 reaction mode or triple quadrupole ICP-MS (ICP-QQQ) in mass-shift mode (O2 and O2/H2). Analysis by collision cell ICP-MS significantly over-estimated As and Se concentration due to REE doubly charged formation; mathematical correction increased the accuracy of analysis but is prone to error when analyte concentration and sensitivity is low and interferent is high. For Se, H2 reaction mode was effective in suppressing Gd2+ leading to accurate determination of Se in both SRMs without the need for mathematical correction. ICP-QQQ using mass-shift mode for As+ from m/z 75 to AsO+ at m/z 91 and Se+ from m/z 78 to SeO+ at m/z 94 alleviated doubly charged effects and resulted in accurate determination of As and Se in both SRMs without the need for correction equations. Zr and Mo isobars at 91 and 94 were shown to be effectively rejected by the MS/MS capability of the ICP-QQQ.
... By contrast, the use of H2 showed limitations. Jackson et al., 2015). Such removal may be explained either by 90 ZrH + formation (Harrington et al., 2014;Epov et al., 2003) although it should be limited (Sugiyama and Nakano, 2014), or charge exchange (Harrington et al., 2014). ...
... Such removal may be explained either by 90 ZrH + formation (Harrington et al., 2014;Epov et al., 2003) although it should be limited (Sugiyama and Nakano, 2014), or charge exchange (Harrington et al., 2014). By contrast, all tested He modes were found to increase this interference confirming the inefficiency of He for limiting the formation of doubly charged ions (Jackson et al., 2015;Yamada, 2015 Yb and 175 Lu), He flow rate was first increased at 5 mL min -1 with a KED maintained at 5 V or increased to 7 V. However, these modes were still not robust enough for removing polyatomic interferences such as gadolinium oxides and hydroxides on ytterbium isotopes. ...
Development of quantification method on ICP-MS for the quantification of Rare Earth Elements and Platinum Group Elements in river water and wastewater effluent present at ultra-trace level. Development of passive samplers (DGT) for the quantification of Platinum Group Elements
... The triple quadrupole has even found widespread use in elemental analysis, in inductively coupled plasma (ICP/MS) [26]. Although an elemental (atomic) ion can't be fragmented by CID in the collision quadrupole, polyatomic ions that fall at the same m/z can be fragmented or reacted to change their m/z [26]. ...
... The triple quadrupole has even found widespread use in elemental analysis, in inductively coupled plasma (ICP/MS) [26]. Although an elemental (atomic) ion can't be fragmented by CID in the collision quadrupole, polyatomic ions that fall at the same m/z can be fragmented or reacted to change their m/z [26]. One can also take advantage of the fact that interfering polyatomic ions will lose more kinetic energy in the collision cell than will atomic ions [27]. ...
... It should be however noted that the use of H 2 significantly reduced the amount of doubly charged 90 Zr 2+ interference onto 45 Sc. Removal of doubly charged species by H 2 has already been observed for other elements [41,42]. Such removal may be explained either by 90 ZrH + formation [41,43] (although it should be limited [44]) , or charge exchange [41]. ...
... Such removal may be explained either by 90 ZrH + formation [41,43] (although it should be limited [44]) , or charge exchange [41]. By contrast, all tested He modes were found to increase this interference confirming the inefficiency of He for limiting the formation of doubly charged ions [42,45]. However, this type of interference only concerned Sc. ...
The present study is based on the use of a conventional quadrupole ICP-MS for determining directly rare earth elements (REEs) in both fresh or slightly saline waters and digested sediments. The development of a robust method using a collision reaction cell (different collision gases and fluxes have been tested) and kinetic energy discrimination is proposed for the accurate quantification of REEs without any mathematical corrections and preconcentration steps. The choice of He gas over H2 and its flow in the collision reaction cell as well as the isotopes studied are thoroughly discussed with the aim of reducing drastically interferences. The exhaustive list of interferences (argides, chlorides, oxides, hydroxides, hydrides and doubly charged) have been investigated for the first time at different concentration levels, relevant with those found in environmental matrices based on the FORum of European Geological Surveys (FOREGS) database. The interfering element concentrations have been determined and summarized. Although the impact of barium interferences onto europium and the impossibility to measure Sc have been pointed out, this method has been validated for all the other REEs in aquatic environmental matrices by studying the recoveries of spiked natural waters (5 commercially available mineral waters with dry residues ranging from 22 to 2513 mg L⁻¹ and a filtrated natural river water from Northern France) with relevant concentrations of REEs. Standard reference materials (i.e. three waters (AQUA-1, SLRS-6 and SLEW-3) and four sediments (BCR-667, HISS-1, Metranal-1 and PACS-3)) were also analysed to ensure the robustness of the method.
... 8 ICP-MS instruments have evolved quickly in the past few decades. New technologies to overcome the problems faced in the analysis of challenging samples have been developed, such as collision and reaction cells to overcome interferences from polyatomic ions and doubly charged ions, [12][13][14][15][16] tandem MS/MS systems which allow selectivity towards reaction cell mode, 17 hyperbolic quadrupoles with <1 a.m.u resolution, and 10 À7 abundance sensitivity features. 11 Regarding the sample introduction system, aerosol dilution has been recently proposed for the analysis of complex samples, such as urine and dialysis solution, 18 saline water, 19 honey, 20 high-salt groundwater, 21 geological materials 22 and edible salts. ...
... The correlation between the predicted and observed values from the model is shown in Fig. SM1b, † wherein satisfactory correlation (R 2 ¼ 0.97) between the data was obtained. According to Jackson et al., 15 the increase of the He gas ow rate increases doubly charged ion formation, due to the reduction of relative signal intensity of singly charged ions compared to doubly charged ions, caused by KED, but no mention on the inuence of the dilution gas has been reported. Results from the present experiment can be associated with the increase in the plasma temperature caused by the aerosol dilution, since less solvent is introduced into the plasma, producing a higher energy condition to promote second ionization processes. ...
In this work, a method for the direct analysis of liquid drug samples by inductively coupled plasma mass spectromety (ICP-MS) with aerosol dilution was proposed. Multivariate studies were executed for optimization of ICP-MS parameters (sample depth, aerosol dilution gas-flow and He gas-flow) using a representative diluted drug sample aiming appropriate plasma robustness parameters (140Ce2+/140Ce+ and 140Ce16O+/140Ce+ ratios), as well as sensitivity for Ag, As, Au, Ba, Cd, Co, Cr, Cu, Hg, Ir, Li, Mo, Ni, Os, Pb, Pd, Pt, Rh, Ru, Sb, Se, Sn, Tl and V, the elemental impurities in USP Chapter 232 protocol. Results showed that dilution gas had major role on doubly-charged and oxide ions formation. A robust plasma condition was achieved (i.e., 140Ce2+/140Ce+ < 0.9% and 140Ce16O+/140Ce+ < 0.3%) when 0.40 L min-1 dilution gas flow was used. The combination of collision gas and dilution gas flow rates was the key feature for minimizing (or even removing) polyatomic interferences. It was found that collision cell benefits from less sample matrix introduction provided by aerosol dilution. A validation protocol has been executed and reported for a liquid drug for hepatic disorders using the optimized procedure, and results successfully met the requirements of USP Chapter 233, wherein appropriate figures of merit (R>0.995, RSD<6.2% for precision tests, RSD<14% for intermediary precision test, and 88-125% recoveries for 50-fold diluted spiked sample with different J concentrations) were obtained. This study provided useful information about the benefits of aerosol dilution and demonstrates that ICP-MS with aerosol dilution is a reliable method for the direct analysis of liquid drug samples in order to attend the USP Chapters 232 and 233 requirements.
... Various techniques have been developed to eliminate or reduce isobaric interferences in the detection of arsenic at mass-to-charge ratio of 75. For polyatomic interferences, a collision/reaction cell can be used to eliminate the interfering ions by introducing collision gas (e.g., helium), reaction gas (e.g., oxygen, hydrogen, CH 3 F), or a mixture of two gases into the ICP-MS [107]. Recently, the use of ICP with triple quadrupole tandem mass spectrometry (ICP-QQQ) helped to remove isobaric interferences, reduce background, and improve selectivity compared to the traditional single quadrupole ICP-MS [107]. ...
... For polyatomic interferences, a collision/reaction cell can be used to eliminate the interfering ions by introducing collision gas (e.g., helium), reaction gas (e.g., oxygen, hydrogen, CH 3 F), or a mixture of two gases into the ICP-MS [107]. Recently, the use of ICP with triple quadrupole tandem mass spectrometry (ICP-QQQ) helped to remove isobaric interferences, reduce background, and improve selectivity compared to the traditional single quadrupole ICP-MS [107]. ...
More than 100 different arsenic species of diverse characteristics are present in the environment and biological systems. The identification and quantification of individual arsenic species are critical to understanding the distribution, environmental fate and behaviour, metabolism, and toxicity of arsenic. This review summarizes sample preparation, separation, detection, and method validation for arsenic speciation analysis. An emphasis is placed on chromatographic separation techniques, relating the physicochemical properties of arsenic species to their efficient separation. Anion exchange, cation exchange, reversed-phase, ion pair, and size exclusion chromatography are useful to separate various arsenic species. Recent research has explored hydrophilic interaction liquid chromatography (HILIC), multiple separation mechanisms, and testing of fluorophenyl and graphene oxide stationary phases for the separation of arsenic species. Sample preparation, extraction of arsenic species, recovery of arsenic species from separation columns, and method validation are discussed in light of their importance to the integrity and accuracy of speciation analysis.
... Compared to Q-ICP-MS, which has a common IDL of around 10 pg/g, the QQQ-ICP-MS is more sensitive and has a lower IDL (around 1 pg/g). Some ultra-trace elements are not detectable for Q-ICP-MS especially when interferences are problematical, but can be determined by QQQ-ICP-MS (e.g., rare earth elements, P, S etc.) [45]. The QQQ-ICP-MS is able to remove or minimize polyatomic interferences (e.g., 75 As + and 40 Ar 35 Cl + ), isobaric interferences (e.g., 40 K + and 40 Ar + ), and non-mono-charged interferences (e.g., 78 Se + and 156 Gd 2+ ) [45], which are the most common interferences in mass spectrometry, while Q-ICP-MS is not. ...
... Some ultra-trace elements are not detectable for Q-ICP-MS especially when interferences are problematical, but can be determined by QQQ-ICP-MS (e.g., rare earth elements, P, S etc.) [45]. The QQQ-ICP-MS is able to remove or minimize polyatomic interferences (e.g., 75 As + and 40 Ar 35 Cl + ), isobaric interferences (e.g., 40 K + and 40 Ar + ), and non-mono-charged interferences (e.g., 78 Se + and 156 Gd 2+ ) [45], which are the most common interferences in mass spectrometry, while Q-ICP-MS is not. Walkner et al. (2017) [40] reported the interferences removal technique of QQQ-ICP-MS clearly in detail. ...
The objective of this study was to develop an effective and routine single sample preparation method to
accurately and precisely analyze multiple elements (up to 57) in crude oils using both an inductively coupled
plasma-optical emission spectrometer (ICP-OES) for high abundance elements and a triple
quadrupole-inductively coupled plasma-mass spectrometer (QQQ-ICP-MS) (or ICP-MS) for low abundance
trace and ultra-trace elements. A critical aspect of this study was to develop a single sample preparation
method that could be effective in analyzing the largest number of quantifiable elements with
instruments used in tandem to cover a wider and more practical combined dynamic range. Three sample
preparation techniques were investigated and tested, including high pressure combustion with strongacid
digestion, high pressure and high temperature strong-acid digestion within Parr bombs, and high
temperature and high pressure digestions in a Single Reaction Chamber (SRC) microwave. For the combustion
method, no element showed recovery above 75%, thus this method was deemed unacceptable for
accurate and precise analysis of crude oil. Average recoveries ranging from 94% to 106% for 19 analytes
were achieved with high pressure and high temperature acid digestion within Parr bombs. A drawback of
the method, however, was a rather small sample sizes (100 mg) that could be achieved without venting,
which places limitations on detection and quantitation limits of large numbers of low abundance analytes
in natural crude oils. The best of the SRC microwave-assisted acid digestion tests, however, was also
shown to be acceptable for 19 analytes using a certified organometallic standard, with average recoveries
ranging from 93% to 113%. Because of rapid sample throughput and the larger sample sizes (1.2 g sample
size per digestion session) that can be accommodated with the single reaction chamber microwave digestion
technique, better method detection and quantification limits and high precision on a range of low abundance elements could be achieved. We also then successfully tested the recovery of 53 elements
with this SRC microwave method by adding a multi-element spike to Conostan base oil. This optimum
SRC digestion method tested was then used to examine a NIST natural crude oil research material
(NIST RM 8505) in an attempt to quantify up to 57 elements. The mean vanadium concentration (mass
fraction) is reported as 390 ± 0.4 mg/g, the mean value of 5 replicate digestions by our method, which
agrees well with the recommended value for the only element recommended for NIST 8505 of
390 ± 10 mg/g. The number of quantified analytes for the RM 8505 was further extended to a total of
52 elements with RSDs <5% for 38 elements, between 5% and 10% for 10 elements, and between 10%
and 15.6% for 4 elements, all of which met our acceptability limits set at �20% RSD. Of the 57 elements
analyzed in RM 8505, certain elements B, Nb, and W, although above method quantitation limits, were judged unacceptable because RSDs were �31.4%, whereas Ag and Tl were below method quantitation
limits, and their RSDs were �44.2% and judged unacceptable. However, these elements have been quantified
in other natural crude oils with higher abundances, which indicates that up to 57 elements can be
potentially assessed in crude oils or refined oils with this method. The NIST RM 8505 crude oil reported
here and others are being evaluated as potential natural crude oil standards to provide references values
for more routine multi-element analysis.
... The 78 Se isotope is also hampered by doubly charged ion interferences from rare earth elements (REEs). REEs are immobile in soils, and as a result, certain sediments are relatively enriched in REEs (Jackson, Liba, and Nelson 2014). Doubly charged interferences such as 156 Gd þþ , and 154 Dy þþ are formed through secondary ionization and impact 78 Se at half the mass (Nakamura, Kubota, and Ohta 2023). ...
... ICP with triple quadrupole tandem mass spectrometry (ICP-QQQ) helps to eliminate isobaric interference, lessen background noise, and enhance selectivity compared to ordinary single quadrupole ICP-MS. 98 There are numerous ways to reduce this interference issue in ICP-MS. Polyatomic interference can be reduced by introducing a different gas to the argon plasma, such as nitrogen, oxygen, air, helium, or hydrogen, which can also reduce the inherent polyatomic interference. ...
Arsenic (As) speciation is an interesting topic because it is well recognized that the toxicity of this metalloid ultimately depends on its chemical form. More than 300 arsenicals exist naturally. However, As can be present in four oxidation states: As−III, As⁰, AsIII and AsV. Long-term exposure to As from different sources, such as anthropogenic processes, or water, fauna and flora contaminated with As, has put human health at risk for decades. There are many side-effects correlated with exposure to InAs species, such as skin problems, respiratory diseases, kidney problems, cardiovascular diseases and even cancer. There are different levels and types of As in foods, particularly in vegetables. Furthermore, different chemical methods and techniques have been developed. Therefore, this review focuses on the general properties of various approaches used to identify As species in vegetation samples published worldwide. This includes various approaches (different solvents and techniques) used to extract As species from the matrix. Then, versatile chromatographic and non-chromatographic systems to separate different forms of As are reviewed. Finally, the general properties of the most common instruments used to detect As species from samples of interest are listed.
... Single quadrupole instruments with a helium collision cell or an H 2 reaction cell could not effectively reduce the interference from the doubly charged 150 Nd 2+ and 150 Sm 2+ . Jackson et al. (2015) eliminated both chloride and doubly charged ion interferences while maintaining extremely low detection limits (0.001 μg/L for arsenic) using a triple quadrupole mass spectrometer (QqQ). Such efficient performance was realized in 'mass shift' mode, in which ions were filtered at m/z 75 in Q 1 , and then the transmitted ions reacted with O 2 in the reaction cell (Q 2 ) to form AsO + , which was followed by mass filtration at m/z 91 in Q 3 . ...
Food and water are main sources of human exposure to arsenic. It is important to determine arsenic species in food because toxicities of arsenic vary greatly with its chemical speciation. Extensive research has focused on high concentrations of arsenic species in marine organisms. The concentrations of arsenic species in freshwater fish are much lower, and their determination presents analytical challenges. We summarize in this review the current state of knowledge on arsenic speciation in freshwater fish and discuss challenges and research needs. Fish samples are typically homogenized, and arsenic species extracted using water/methanol with the assistance of sonication and enzyme treatment. Arsenic species in the extracts are commonly separated using high performance liquid chromatography (HPLC) and detected using inductively coupled plasma mass spectrometry (ICPMS). Electrospray ionization tandem mass spectrometry (ESI MS/MS), used in combination with HPLC and ICPMS, provides complementary information for the identification and characterization of arsenic species. The methods and perspectives discussed in this review, covering sample preparation, chromatography separation, and mass spectrometry detection, are directed to arsenic speciation in freshwater fish and also applicable to studies of other food items. Despite progresses made in arsenic speciation analysis, a large fraction of total arsenic in freshwater fish remains unidentified. It is challenging to identify and quantify arsenic species present in complex sample matrices at very low concentrations. Further research is needed to improve the extraction efficiency, chromatographic resolution, detection sensitivity, and characterization capability.
... ICP-MS is a practical approach for analyzing these kinds of samples. Interferences must be eliminated before performing As analysis using ICP-MS since the salt (NaCl) has the same mass-to-charge ratio as As [167][168][169]. One of the hybrid methods must involve the instrumentation required to conduct speciation investigations. ...
Heavy metal and metalloid poisoning in the environment and food has piqued the public’s interest since it poses significant hazards to the ecological system and human health. In food, several metals, including cadmium (Cd), lead (Pb), mercury (Hg), tin (Sn), manganese (Mn), and aluminium (Al), and metalloids, including arsenic (As), antimony (Sb), and selenium (Se), pose a severe threat to human health. It is of utmost importance to detect even minute quantities of these toxic elements and this must be efficiently determined to understand their risk. Several traditional and advanced technologies, including atomic absorption spectrometry (AAS), spectrofluorimetry, inductively coupled plasma spectrometry, e-tongues, electrochemical aptasensors, Raman spectroscopy, and fluorescence sensors, among other techniques, have proven highly beneficial in quantifying even the minute concentrations of heavy metals and metalloids in food and dietary supplements. Hence, this review aims to understand the toxicity of these metals and metalloids in food and to shed light on the emerging technologies for their detection.
... When compared to standard single quadrupole ICP-MS, the use of ICP with triple quadrupole tandem mass spectrometry (ICP-QQQ) helps to remove isobaric interferences, reduce background noise, and improve selectivity. 25 2.1.4. Laser induced breakdown spectroscopy (LIBS). ...
Arsenic occurs in the natural environment in four oxidation states: As(V), As(III), As(0) and As(−III). The behavior of arsenic species changes depending on the biotic or abiotic conditions in water....
... Furthermore, with the new generation of ICP-MS/MS equipped with a collision-reaction cell (CRC) between two quadrupoles in tandem, better sensitivity of selenium was obtained. Plus, spectral polyatomic interferences can be eliminated with an appropriate CRC gas, enabling the accurate determination of selenium in complex matrices [27][28][29] . ...
An enzyme-assisted extraction and an ion pairing reversed phase chromatography (IP-RPC) coupled to inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) method were established for the simultaneous analysis of five selenium species in rice: selenious acid (SeIV), selenic acid (SeVI), selenocystine (SeCys2), methylselenocysteine (SeMeCys) and selenomethionine (SeMet). Optimal extraction efficiencies were obtained by using 15 mg protease XIV, water bath temperature of 45°C, pH of 6.5 and incubation of six hours. The total extracted Se species account for 92.5-109.3 % of the total Se in rice. The instrumental limits of detection for five selenium species ranged from 0.04 to 0.12 ng Se g⁻¹. Spike recovery experiments performed on rice samples were in the range of 96.1-102.9 % for all analytes except for SeCys2 (66.1-77.1 %). A consistency of Se elemental response was observed among Se species analyzed in this study as the ratio of linear equation slope ranged from 1.020 to 1.036 (SeIV as reference) in rice matrix. The developed compound-independent calibration method was applied to detect Se species in eleven rice samples from China. Both selenium-enriched rice and regular rice were predominated with SeMet, accounting for ∼89.4 % of total selenium.
... Various techniques have been developed to eliminate or reduce isobaric interference in the detection of arsenic by mass-to-charge ratio. Recently, compared with the traditional single quadrupole ICP-MS, the combination of ICP and triple quadrupole tandem mass spectrometry (ICP-QQQ ) helps to eliminate isobaric interference, reduce background, and improve selectivity [156]. Quantification is performed by preparing standard solutions of commercially available substances, such as iAs(III), iAs(V), MA, DMA, and AB. ...
There are more than 100 different arsenic with different characteristics in the soil-water-plant ecosystem. The identification and quantification of individual arsenic species is essential for understanding the distribution, environmental fate and behavior, metabolism and toxicity of arsenic. Due to the hazardous nature of arsenic, people have a high interest in the measurement of arsenic species. The reaction of the formation of arsenic speciation in the soil-water-plant environment is briefly studied. There is little information on methods used to quantify arsenic forms and species in contaminated soil, water and plant. The purpose of this article is to understand the available sample pretreatment, extraction, separation, detection and method validation techniques for arsenic speciation analysis of arsenic species in soil, water and plant. The performances of various sample preparation and extraction processes, as well as effective separation techniques, that contribute greatly to excellent sensitivity and selectivity in arsenic speciation when coupling with suitable detection mode, and method validity are discussed. The outlines of arsenic speciation techniques are discussed in view of the importance to the completeness and accuracy of analytical data in the soil-water-plant samples. To develop cheap, fast, sensitive, and reproducible techniques with low detection limits, still needed to confine research on arsenic speciation present in environmental matrices.
... When conducting As analysis by inductively coupled plasma mass spectrometry (ICP−MS), the interferences must be removed before analysis as the salt (NaCl) has the same mass-to-charge ratio (m/z value) as As. 11 For trace element analysis, it is always important to select a more sensitive analytical method and validate its application to subject samples. 12 ICP−MS has been reported in the literature as the most effective quantitative analytical method to measure trace elements in food samples due to its high sensitivity and selectivity. ...
Toxic elements (Cd, Pb, and As) accumulate into the environment by industrialization and natural phenomena and then pass to organisms. Analysis of toxic elements in food must be accurately carried out on a regular basis so as to avoid any adverse impact. Salted foods are difficult samples and accurate analysis of As is not easy due to salt interference. In this study, analysis of As was carried without influence of salts in three types of salted foods via an analytical method, which was validated using spiking recovery experiments and by analyzing certified reference materials. As a result, toxic elements were detected in all samples but none of these exceeded the World Health Organization recommended limits. Among the As species, arsenobetaine (AsB) was the most abundant, while inorganic As was below the detection limit in all samples. All the analyzed salted food samples appeared to be safe for consumption. In addition, the analysis of sea shrimp, freshwater shrimp, and seawater verified As bioaccumulation in these organisms from the environment.
... 14 This approach facilitates lower detection limits and background signal than those that can be achieved with single quadrupole ICP-MS. [15][16][17] Jackson et al 18 have reported that the LOD of 80 SeO + and 75 As + in ICP-QMS decreases 10-fold compared with the conventional reaction cell in single quadrupole ICP-MS. This allows for more accurate analysis at the ultra-trace level, particularly for monoisotopic elements, such as 75 As + suffering from 40 As 35 Cl + and 38 Ar 37 Cl + , or elements having highly abundant isotopes, such as 80 Se + (49.6%) suffering from 40 Ar 40 Ar + , bromine hydrogen ( 79 Br 1 H + ), and gadolinium ( 160 Gd 2+ ). ...
Objectives
This review aims to describe the principles underlying different types of inductively coupled plasma mass spectrometry (ICP-MS), and major technical advancements that reduce spectral interferences, as well as their suitability and wide applications in clinical laboratories.
Methods
A literature survey was performed to review the technical aspects of ICP-MS, ICP-MS/MS, high-resolution ICP-MS, and their applications in disease diagnosis and monitoring.
Results
Compared to the atomic absorption spectrometry and ICP-optical emission spectrometry, ICP-MS has advantages including improved precision, sensitivity and accuracy, wide linear dynamic range, multielement measurement capability, and ability to perform isotopic analysis. Technical advancements, such as collision/reaction cells, triple quadrupole ICP-MS, and sector-field ICP-MS, have been introduced to improve resolving power and reduce interferences. Cases are discussed that highlight the clinical applications of ICP-MS including determination of toxic elements, quantification of nutritional elements, monitoring elemental deficiency in metabolic disease, and multielement analysis.
Conclusions
This review provides insight on the strategies of elemental analysis in clinical laboratories and demonstrates current and emerging clinical applications of ICP-MS.
... Several analytical methods have been established to determine the concentration of arsenic in various samples. Many analytical methods with expensive instrumental have been applied to detect arsenic in environmental matrices, such as high performance liquid chromatography combined with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) [8], hydride generation atomic fluorescence spectrometry (HG-AFS) [9], atomic fluorescence spectrometry (AFS) [10], inductively coupled plasma mass spectrometry (ICP-MS) [11], electrochemical method [12][13][14] and atomic absorption spectroscopy (AAS) [15]. Furthermore, various simple, rapid, sensitive and inexpensive methods was also investigated. ...
A colorimetric probe for determination of As(III) ions in aqueous solutions on basis of localized surface plasmon resonance (LSPR) was synthesized. The dithiothreitol molecules with two end thiols covalently combined with Au Nanorods (AuNRs) with an aspect ratio of 2.9 by Au-S bond to form dithiothreitol coated Au Nanorods (DTT-AuNRs), acting as colorimetric probe for the determination of As(III) ions. With the adding of As(III) ions, the AuNRs will be aggregated and leading the longitudinal SPR absorption band of DTT-AuNRs decrease due to the As(III) ions can bind with three DTT molecules through an As-S linkage. The potential factors affect the response of DTT-AuNRs to As(III) ions including the concentration of DTT, pH values of DTT-AuNRs, reaction time and NaCl concentration were optimized. Under optimum assay conditions, the DTT-AuNRs colorimetric probe has high sensitivity towards As(III) ions with low detection limit of 38 nM by rules of 3σ/k and excellent linear range of 0.13–10.01 μM. The developed colorimetric probe shows high selectivity for As(III) ions sensing and has applied to determine of As(III) in environmental water samples with quantitative spike-recoveries range from 95.2% to 100.4% with low relative standard deviation of less than 4.4% (n = 3).
... Target gases such as hydrogen in mixture with helium gas [8,9] have been used to remove the Ar 2 + interfering ions [4,6], the interference of 40 Ar 35 Cl with As can be decreased through the reaction: 2 40 Ar 35 Cl + + H 2 → 2 40 Ar + + 2HCl [12]. Arsenic ion signal can shift to AsO + by oxidizing agents such as O 2 through the reaction M + + ½ O 2 → MO + [13] or N 2 O [9,14,15] through the reaction M + + N 2 O → MO + + N 2 . As also can be shifted to AsCH 2 + by using CH 3 F as a reaction gas through the reaction M + +CH 3 F → MCH 2 + + HF [16]. ...
A study on the thermochemistry of species (40Ar35Cl+, 59Co16O+, 36Ar38Ar1H+, 38Ar37Cl+, 36Ar39K+, 150Nd++, 150Sm++and 150Eu++) that interfere with arsenic in inductively coupled plasma mass spectrometer was
estimated by Gaussian code. Moreover, (AsCH3F+, AsF+, AsCH2
+, AsCHF+ and AsO+) that result from
the reactions between arsenic and different gases such as H2,O2 and CH3F, which are commonly used in
dynamic reaction cell-inductively coupled plasma- mass spectrometer, have been investigated. The
structures of polyatomic molecules are optimized; ionization energies, heats of formation (ΔfH°
0 and
ΔfH°
298) and proton affinity (PA) of some species are estimated by theoretical calculations using different
methods in Gaussian.
... Determination of total Se concentration is commonly carried out as part of a multielement analysis using ICP-MS. More recently, Se analysis has benefited from the lower detection limits and greater freedom from spectral interferences provided by triple quadrupole ICP-MS (ICP-QQQ) [4,5]. However, the toxicity of Se depends on the chemical form or species in which the Se occurs, so total elemental concentrations do not provide a complete picture of the element's potential toxicity. ...
In the USA, animal feed is subject to regulation under the Federal Food, Drug, and Cosmetic Act (FFDCA), which defines food as “articles used for food or drink for man or other animals”. The US Food and Drug Administration’s (FDA) Center for Veterinary Medicine (CVM) is responsible for regulations relating to the safety of feed intended for animals (including but not limited to horses, cattle, swine, poultry, and fish), under the Animal Feed Safety System (AFSS). The regulations control many aspects of the production, storage, and labeling of animal feed, and the permitted levels of additives and contaminants, such as potentially toxic heavy metals. Selenium (Se) has been approved by the FDA as a supplement for animal feed since the 1970s. The FDA’s current method for Se quantification uses ICP-MS with helium collision/reaction cell (CRC) for control of interferences [1], but the sensitivity of this method is affected when high levels of interferences are present.
... In and Re was added to the samples during analysis to correct for instrument drift. Arsenic was also analyzed as AsO + at m/ z = 91 using O 2 as reaction gas in MS/MS mode, in order to monitor ArCl + (m/z = 75) interferences and doubly charged REE interferences (Jackson et al., 2015). Helium collision and O 2 reaction give similar results which suggest that He collision mode is sufficient for the removal of polyatomic interferences in the HNO 3 and H 2 O 2 matrix. ...
A great deal of research has been devoted to the characterization of metal exposure due to the consumption of vegetables from urban or industrialized areas. It may seem comforting that concentrations in crops, as well as estimated exposure levels, are often found to be below permissible limits. However, we show that even a moderate increase in metal accumulation in crops may result in a significant increase in exposure. We also highlight the importance of assessing exposure levels in relation to a regional baseline. We have analyzed metal (Pb, Cd, As) concentrations in nearly 700 samples from 23 different vegetables, fruits, berries and mushrooms, collected near 21 highly contaminated industrial sites and from reference sites. Metal concentrations generally complied with permissible levels in commercial food and only Pb showed overall higher concentrations around the contaminated sites. Nevertheless, probabilistic exposure assessments revealed that the exposure to all three metals was significantly higher in the population residing around the contaminated sites, for both low-, median- and high consumers. The exposure was about twice as high for Pb and Cd, and four to six times as high for As. Since vegetable consumption alone did not result in exposure above tolerable intakes, it would have been easy to conclude that there is no risk associated with consuming vegetables grown near the contaminated sites. However, when the increase in exposure is quantified, its potential significance is harder to dismiss - especially when considering that exposure via other routes may be elevated in a similar way.
... Tanner et al. (2002) demonstrated that the same reaction gases used to solve the spectral overlap of Ar, ArH, ArO, etc., can be employed for argide ions. In the case of interference by doubly charged ions from REEs, according to Jackson and coworkers (Jackson et al. 2015), the PI of these reactions is between 11 and 12 eV, making the reaction with ammonia (PI ∼10 eV) thermodynamically allowed. However, the same is not true for methane, for which the ionization potential is 12.6 eV. ...
The aim of this work was to evaluate different approaches employing a reaction cell to circumvent spectral interferences over ⁸⁰Se⁺ to increase the sensitivity in the determination of Se by inductively coupled plasma mass spectrometry (ICP-MS). Different gases (NH3, CH4, and O2) were employed, and the operating conditions were optimized by a central composite design, evaluating the effect of the reaction gas flow rate and the rejection parameter q (Rpq) on the limit of detection (LOD) of the method. All reaction gases studied reduced the interference by ⁴⁰Ar2⁺ over ⁸⁰Se⁺, reducing the LOD when compared to the LOD obtained with ICP-MS operating in the standard mode (LOD = 0.2 μg kg⁻¹). A better LOD (0.01 μg kg⁻¹) was obtained with CH4, while 0.1 μg kg⁻¹ was the LOD with NH3. The use of O2 as a reaction gas enabled the determination of Se at m/z 96 (⁸⁰Se¹⁶O⁺) with adequate analytical performance (LOD = 0.03 μg kg⁻¹). The accuracy of the method was evaluated by analyzing the certified reference material (CRM) Selm-1, and the results obtained ranged from 99 to 104% of the certified value. In addition, Se dietary supplements of four different brands and commercial yeast were analyzed, and the major sources of uncertainty were studied. The dietary supplements followed the criteria adopted by Brazilian legislation, although the uncertainty study highlighted the great variation in the Se content of each brand. Clearly, the manufacturing process of dietary supplements needs more rigorous quality control, considering that this product can affect the health of consumers.
Анализ литературных источников показал наличие «слабых» мест при аналитическом контроле мышьяка в объектах ихтиофауны и водорослях, используемых в пищевой продукции. Для того, чтобы сделать заключение о качестве рыбы необходимо выявление форм нахождения мышьяка: либо неорганическая (наиболее токсичная), либо органические соединения, являющиеся токсически инертными или малотоксичными. В результате проведения мониторинговых исследований было выявлено, что наибольшее валовое содержание мышьяка обнаружено в ламинарии-1,510 мг/кг, при этом доля неорганической формы самая высокая-до 70,5% от всего количества мышьяка. В других образцах неорганический мышьяк не найден. Во всех исследуемых образцах монометиларсиновая кислота не обнаружена. Доля диметиларсиновой кислоты зависит от среды обитания и источников питания. Ключевые слова: мышьяк, ВЭЖХ-ИСП-МС, аналитический контроль, элементорганические соединения. ________________________________________________________________________________ Indication and identification of hazardous substances UDC 543.42:615.9
Environmental monitoring programs that target fish tissues for selenium (Se) analysis present unique sampling and analytical challenges. Se monitoring programs ideally focus on egg/ovary sampling but frequently sample multiple tissues with varying lipid content, often target small-bodied fish species due to their small home ranges, and require reporting in units of dry weight. Additionally, there is a growing impetus for non-lethal tissue sampling in fish monitoring. As a result, Se monitoring programs often generate low-weight tissue samples of varying lipid content, which challenges analytical laboratories to quantify tissue selenium concentrations accurately, precisely, and at desired detection limits. The objective of this study was to stress-test some conventional analytical techniques used by commercial laboratories in terms of their ability to maintain data quality objectives in the face of sample weight constraints. Four laboratories analyzed blind a suite of identical samples, and data were compared against a priori data quality objectives for accuracy, precision, and sensitivity. Data quality tended to decrease with decreasing sample weight, particularly when samples were less than the minimum weights requested by the participating laboratories; however, effects of sample weight on data quality were not consistent among laboratories or tissue types. This study has implications for accurately describing regulatory compliance in selenium monitoring programs, highlighting some important considerations for achieving high data quality from low-weight samples.
Three 1 2 mass oriented rare earth element (REE) M2+ correction approaches (fixed factor, a dual internal standard, and an in-sample) are evaluated for use in an ICP-MS environmental method update. The multi-variant-based evaluation includes analyzing the same 19 REE-fortified matrices on eight different days over a two-month period using two instrument tunes. These REE-fortified matrices were also analyzed using HR-ICP-MS and ICP-MS/MS to estimate the reference value for use in the principal component analysis (PCA) and hierarchical modeling evaluation. A fixed factor is unable to compensate for matrix and mass dependent drift and because of this it generates the largest across matrix, tune, and day 95th percent confidence bounds for the REE corrections on both As (1.1 ppb) and Se (23 ppb) using samples fortified with 100 ppb Nd, Sm & Gd. The PCA analysis indicated that M2+ ions cluster together across matrix, tune and day better than M1+ and these tighter correlations are reflected in reduced 95th percentile confidence bounds for dual M2+ internal standards (M2+; As = 0.3 ppb; Se = 5.4 ppb; n = 704) relative to M1+ internal standards (M1+; As = 0.6 ppb; Se = 12.0 ppb; n = 1056). The use of an in-sample M2+ correction produced comparable 95th percent confidence bounds (As = 0.2 ppb; Se = 3.4 ppb; n = 352) relative to the M2+ internal standard approaches. Finally, the hierarchical modeling indicated M2+ ions as internal standards tend to minimize the across day variability induced by cone changes and the daily reoccurring matrix shifts in the M2+/M1+ ratio associated with 250 ppm matrices of Na, Ca, and Mg. This internal standard driven reduction in variability can be beneficial in compliance monitoring methods.
Most spectral interferences that arise in ICP-MS are caused by matrix or plasma-based ion overlaps on an analyte ion. These interferences can be effectively controlled using collision/reaction cell (CRC) technology operating in helium (He) collision cell mode, improving the data quality of trace elements in a variety of matrices. However, spectral interferences caused by doubly charged ions (M⁺⁺), such as rare-earth element (REE⁺⁺) ion interferences on arsenic (As) and selenium (Se), are difficult to resolve using single quadrupole ICP-MS operating in He collision cell mode. Therefore, a new method was investigated using hydrogen (H2) as a collision cell gas and kinetic energy discrimination (KED) to separate the ions. For KED to be successful there needs to be a difference in the collisional cross-section of the analyte ion and interfering ion. The collisional cross-section of a doubly charged ion is greater with H2 molecules than He (the traditional ICP-MS collision cell gas) due to the higher polarizability of H2. Utilizing these physical characteristics, the reduction of M⁺⁺ interferences by KED was investigated both theoretically and experimentally. The developed low kinetic energy H2 collision cell method correctly measured 1 μg L⁻¹ of As and Se in the presence of 0.5 mg L⁻¹ each of 16 REEs. No mathematical interference correction equations were needed. A conventional He collision cell method provided a false positive result for As and Se of more than 10 μg L⁻¹.
Since the development of atomic spectrometry, trace element and isotopic analysis has been mainly based on the monitoring of atomic spectra and monoionic species. However, according to the literature and considering the current instrumental developments, it seems that some of the remaining challenges in this field can be mitigated via the measurement of molecular spectra or of polyatomic ions. This review discusses recent advances in three of the most important atomic techniques (laser-induced breakdown spectrometry, high-resolution continuum source atomic absorption spectrometry and inductively coupled plasma mass spectrometry) and how the monitoring of such molecules or polyatomic ions containing the target analyte enables attaining better selectivity and opens new ways to determine non-metals and to obtain isotopic information.
Selenium (Se) is an essential trace element in human health and therefore its concentration in biological samples (biofluids and tissues) is used as an indicator of health and nutritional status. In humans, selenium’s biological activity occurs through the 25 identified selenoproteins. As total selenium concentration encompasses both functional selenoproteins, small selenocompounds and other selenium-binding proteins, selenium speciation, rather than total concentration, is critical in order to assess functional selenium. Previously, quantitative identification of selenoproteins required laborious techniques that were often slow and costly. However, more recent advancements in tandem mass spectrometry have facilitated the qualitative and quantitative identification of these proteins. In light of the current alternatives for understanding selenium biochemistry, we aim to provide a review of the modern applications of electrospray ionisation mass spectrometry (ESI-MS) as an alternative to inductively coupled plasma mass spectrometry (ICP-MS) for qualitative and quantitative selenium speciation.
Chloride widely exists in the environment and will cause serious interference for arsenic speciation analysis. The determination of four arsenic species including arsenite (As(III)), arsenate (As(V)), monomethylarsenate (MMA), and dimethylarsonate (DMA) in samples containing high concentrations of Cl− was carried out in this work by coupling of liquid chromatography (LC) with hydride generation atomic fluorescence spectrometry (HG-AFS). The interference of Cl− was successfully eliminated by coupling two anion-exchange chromatographic columns in series and eluting with 35.0 mmol L−1 (NH4)2HPO4 (pH = 6.00). A novel pre-treatment system was subsequently developed to realize on-line column switch and pre-reduction of As(V). The analysis time was shortened by an isocratic elution but programmed flow rate method, and the sensitivity of As(V) was also enhanced by the introduction of pre-reduction using the developed system. The proposed method can resist at least 10 g L−1 Cl− without any pre-treatment operations. Since LC-HG-AFS is low-cost and can be afforded or self-assembled by most labs, the developed method can be adopted as a routine analysis method for arsenic species in chloride-bearing samples, such as urine and seawater.
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Rare earth elements (REE) can produce M ²⁺ ions in ICP-MS and ¹⁵⁰ Nd ²⁺ , ¹⁵⁰ Sm ²⁺ , and ¹⁵⁶ Gd ²⁺ can produce false positives on ⁷⁵ As and ⁷⁸ Se.
The composition of inorganic elements is a key factor in determining the quality of fruit wines. However, the use of direct sample injection is challenging for multi-elemental analysis of fruit wine samples. In this paper, an analytical method using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was established for determining multiple elements (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg, and Pb) in fruit wine. The fruit wine was diluted using ultrapure water and acidified with nitric acid before injecting into the ICP-MS/MS. Spectral interferences in the complex matrix composition of different fruit wine samples, in the MS/MS mode, were eliminated using mixed reaction gases of O2/H2 and NH3/He/H2 through the mass shift and on-mass methods. The limits of detection ranged from 0.41 to 58.1 ng L-1. This study demonstrates a new approach for multi-elemental analysis in fruit wine with great convenience and high accuracy.
With the wide range of metallic contaminants discharged in the environment, studying the human health requires a growing number of elements to be monitored in biological samples. Hair analysis has been suggested as a suitable tool for biomonitoring environmental and occupational exposure to toxic elements. This study describes a method for the determination of 10 trace elements in hair samples using ICP-QQQ-MS. Combining the power of the MS/MS high-energy Helium mode with the MS/MS O2 mass-shift mode, the method offers great analytical performances with detection limits reaching 0.0014 µg g⁻¹ for As, 0.0016 µg g⁻¹ for Cd, 0.012 µg g⁻¹ for Cr, 0.0035 µg g⁻¹ for Hg, 0.0055 µg g⁻¹ for Mn, 0.10 µg g⁻¹ for Ni, 0.0012 µg g⁻¹ for Sb, 0.0083 µg g⁻¹ for Sn, 0.011 µg g⁻¹ for Se and Pb. The accuracy of the method was tested on a human hair ERM® certified reference material. Percent recoveries varied from 91.3% and 106.9% being always in the acceptance range of 90–110%. For all analysed elements, RSD% of repeatability ranged between 0.6% and 9.0% and those of intermediate precision did not exceed the limit of 20% being always lower than 10% (except for As). The proposed method was applied for the determination of trace elements in hair samples from 20 unexposed subjects. The geometric mean levels were as follows: Cr 0.28 µg g⁻¹, Mn 0.30 µg g⁻¹, Sn 1.04µg g⁻¹, Sb 0.07 µg g⁻¹, Hg 0.42 µg g⁻¹, As 0.02 µg g⁻¹, Cd 0.03 µg g⁻¹, Ni 0.51 µg g⁻¹, Se 0.45 µg g⁻¹ and Pb 1.83 µg g⁻¹. Element concentrations were in the same range with the reported data. The reported results may be useful for environmental exposure assessment or comparisons studies when establishing reference values of trace elements in exposed population.
In determining As and Se in soil samples by ICP-MS, doubly charged ions due to Nd, Sm, and Gd cause severe spectral interferences. In the present work, a separation method of Nd, Sm, and Gd by cation exchange was examined. As a result, it was found that Nd, Sm, and Gd could be removed by cation exchange when the concentration of HCl was smaller than 0.1 mol L⁻¹, while As and Se could be recovered quantitatively. The recovery values of As and Se were 104.7 ± 2.1 % and 100.3 ± 0.4 %, respectively, and their detection limits were 0.006 mg kg⁻¹ and 0.003 mg kg⁻¹; in the case that 1 mol L⁻¹ HCl extracted solution (6 g of soil sample was extracted with 200 mL of 1 mol L⁻¹ HCl) was diluted 50-times and treated with 0.40 g of cation exchange resin. The feasibility of the present method was examined by analyzing soil certified reference material (JSAC 0402). The present method was applicable for the determination of As and Se in various soil samples.
The inorganic arsenic (i-As) in grape products, in particular juice, wine and raisins, collected from the Japanese market was investigated. The concentrations of total As in nine grape concentrated juices ranged from 3 to 20 ng g⁻¹, and more than 80% of the As was inorganic according to the results of speciation by HPLC-ICP-MS. Among them, four samples contained more than 10 ng g⁻¹ of i-As, although 10 ng g⁻¹ of i-As is the limit for apple juice recommended by the U.S. Food and Drug Administration. Moreover, more than 10 ng g⁻¹ of i-As was found in some of the wine and raisin samples, with the total As concentrations ranging from 17 to 37 ng g⁻¹. When fresh grapes were analyzed, As was mainly concentrated in the pericarp and a small amount was found in the fruit, although no As was observed in the branches and the juice. When grapes, including the pericarp, are processed, the As concentration in the products may increase during production processes such as drying, concentration, and ripening.
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Inarguably, one of the major issues concerning ICP-MS is spectral interferences. Around the year of 2000, some ICP-MS manufactures developed collision/reaction cells (CRCs) so as to cope with this issue. Since then, CRCs have undergone continual refinments and improvement for nearly two decades, and eventually became vital devices in today’s quadrupole ICP-MS. In this paper, the latest technological aspects of CRCs are reviewed and their fundamental limitations are clarified. Then follows a discussion about the mechanism for overcoming some of these limitaions by triple quadrupole ICP-MS (ICP-MS/MS). Particulary, this new technology enhances the capability of reaction cells by minimizing the cell-formed interferences and making the mass-shift method truly useful. Many of the interference problems that have remained unresolved for long in ICP-MS are now being resolved. The principles and applications of ICP-MS/MS are described in detail.
L’environnement et la physiologie déterminent les compositions isotopiques du Ca de l’organisme des vertébrés et des mammifères en particulier. Ces constats ont permis de dégager des applications possibles de l’étude des isotopes du Ca, en biologie médicale pour le suivi de l’équilibre osseux chez les mammifères et en (paléo-)écologie pour l’étude des régimes alimentaires actuels et passés des vertébrés. Ces applications sont tributaires d’une meilleure compréhension fondamentale des causes de ces variations. Cette thèse a pour but de déterminer les principales causes de variabilité des compositions isotopiques du Ca chez les mammifères et l’humain. Un protocole d’analyse en solution par MC-ICP-MS est d’abord présenté puis deux méthodes d’échantillonnage sont comparées afin de réaliser des mesures de résolution spatiale accrue dans les tissus minéralisés. L’influence des sources alimentaires de Ca est ensuite discutée. La composition isotopique de l’alimentation humaine est variable du fait des compositions diverses des sources primaires de Ca et dépend particulièrement des proportions de produits laitiers dans l’alimentation. Il est démontré que les transitions nutritionnelles précoces, comme le sevrage du lait maternel, peuvent être tracées par les compositions de l’émail des dents de lait humaines. Les mécanismes des fractionnements isotopiques sont discutés sur la base d’observations chez l’humain et l’animal. Un modèle mathématique permet de dégager des mécanismes expliquant la distribution des isotopes du Ca à travers les tissus et les fluides de l’organisme et met en lumière le rôle prépondérant du rein dans la détermination de la composition isotopique de l’os.
There is increasing environmental concern regarding the emission of selenium (Se) from mining and upgrading of bitumen extracted from the Athabasca bituminous sands (ABS) in northern Alberta, Canada. However, there remains a lack of high quality analytical data for Se in this massive hydrocarbon reserve. Accurate analytical determinations of Se in bitumen from ABS are an important first step toward understanding its potential to be emitted to the environment. This has been a challenge due to the low abundance of Se combined with the preponderance of entrained mineral material (sand, clay) and the generally inadequate sensitivity of analytical methods used in the past. To overcome these issues, samples of ABS ores (McMurray Formation) underwent a toluene extraction procedure under ultra-clean lab conditions to separate bitumen from mineral particles. Separated bitumen, residual mineral material, and bulk ores were then subjected to acid-digestion and analysis using inductively coupled plasma sector-field mass spectrometry (ICP-SFMS) as well as hydride generation atomic fluorescence spectroscopy (HG-AFS). Unlike many other potentially toxic trace elements (Ag, As, Be, Cd, Cu, Pb, Sb, Tl and Zn) which exist almost exclusively in the mineral fraction, Se was found primarily (ca. 80%) in the organic (bitumen) fraction. Sulphur was determined in the same acid digests using both ICP-SFMS and inductively coupled plasma-optical emission spectroscopy (ICP-OES) and it too, was found almost exclusively in the bitumen fraction. Despite the limited number of samples available to our study, the positive, linear correlation between Se and S concentrations in bitumen suggests that S concentrations can be used as a guide to estimate their Se content. Given that Se is found mainly in the organic fraction of the ABS, there is considerable potential for mobilization of this element during upgrading and refining. The analytical methods successfully employed here have sufficient sensitivity to support studies of Se contamination of environmental media in the ABS region.
A new method of mathematical correction of the results of analysis, obtained by inductively coupled plasma mass spectrometry, for the elimination of the interference of doubly charged ion was proposed. This method bases on the use recording isotope signals in two operation modes of the spectrometer:standard and with using a collision cell (Kinetic energy discrimination/KED mode). The mathematical correction of the results of arsenic determination in model solutions was performed using two processes, standard and proposed in this paper. The accuracy and repeatability of the results were compared.
A method is proposed for the determination of selenium at low concentration in coal by collision/reaction cell technology inductively coupled plasma mass spectrometry (CRC-ICP-MS). Samples were decomposed by high pressure microwave-assisted wet digestion (MAWD) using 250 mg of coal, a mixture of 5 mL of 14.4 mol L⁻¹ HNO3 and 1 mL of 40% HF and 70 min of heating program (200 °C and 40 bar). Hydrogen gas used in the collision/reaction cell was investigated to minimize the argon-based interferences at m/z 77, 78 and 80. The rejection parameter (RPq) and the H2 gas flow rate were set to 0.45 and 4.8 mL min⁻¹, respectively. The use of H2 in the cell resulted in other polyatomic interferences, such as ⁷⁶Ge¹H⁺, ⁷⁹Br¹H⁺ and ⁸¹Br¹H⁺, which impaired Se determination using ⁷⁷Se, ⁸⁰Se and ⁸²Se isotopes, thus Se determination was carried out by monitoring only ⁷⁸Se isotope. Selenium was determined in certified reference materials of coal (NIST 1635 and SARM 20) and an agreement better than 95% was observed between the results obtained by CRC-ICP-MS and the certified values. Under optimized conditions, the instrumental limit of detection was 0.01 μg L⁻¹ and the method limit of detection was 0.01 μg g⁻¹, which was suitable for Se determination at very low concentration in coal.
Development of a new sample preparation method for crude or fuel oils by mineralization utilizing single reaction chamber microwave for broader multi-element analysis by ICP-QQQ-MS and ICP-OES. Online link: http://www.searchanddiscovery.com/pdfz/documents/2017/42142yang/ndx_yang.pdf.html
A highly sensitive method was developed for the simultaneous separation and determination of organic and inorganic selenium species in rice by ion-pairing reversed-phase chromatography combined with inductively coupled plasma tandem mass spectrometry. To achieve a good separation of these species, a comparison between anion-exchange chromatography and ion-pairing reversed-phase chromatography was performed. The results indicated that ion-pairing reversed-phase chromatography was more suitable due to better separation and higher sensitivity for all analytes. In this case, a StableBond C18 column proved to be more robust or to have a better resolution than other C18 columns, when 0.5 mM tetrabutylammonium hydroxide and 10 mM ammonium acetate at pH 5.5 were used as the mobile phase. Moreover, an excellent sensitivity was obtained in terms of interferences by means of tandem mass spectrometry in the hydrogen mode. The detection limits were 0.02–0.12 μg L–1, and recoveries of five selenium species were 75–114%, with relative standard deviations ≤ 9.4%. This method was successfully applied to the analysis of rice samples. Compared with previous studies, the proposed method not only gave comparable results when used for measuring selenium-enriched rice, but it can provide greater sensitivity for the detection of low concentrations of selenium species in rice.
Arsenic speciation in seafood after several culinary treatments was performed and AsB, As(iii), DMA, MMA and As(v) species were determined by liquid chromatography hyphenated to triple-quadrupole inductively coupled plasma mass spectrometry (LC-ICP-MS/MS) using O2 as the reaction gas for the conversion of ⁷⁵As to ⁷⁵As¹⁶O. The influence of culinary treatments (boiling, frying and sautéing) with or without the addition of spices (salt, lemon juice and garlic) on the As species in blacktip shark and Asian tiger shrimp was investigated. Arsenic species were extracted by using a 30 mmol L⁻¹ HNO3 solution. Ammonium phosphate (10 mmol L⁻¹) was used as the mobile phase. The influence of pH and the addition of 1% (v/v) methanol were investigated. Oil, water, butter and the spices used during cooking were analysed to perform a close mass balance of the total As. The speciation method was also employed for a certified reference material (CRM, DORM-3), and the accuracy was evaluated by statistical comparison between the certified value and the total As concentration determined by ICP-MS after acid digestion and also by a comparison of the sum of As species with the total As. It was demonstrated that the culinary treatments practically did not influence the stability of As species in uncooked seafood. On the other hand, significant analyte losses (from 15 up to 45%) were observed for boiled seafood. The speciation analysis method presented accuracy and robustness for both raw seafood and seafood after the culinary treatments. The limits of quantification were 4, 21, 4, 9 and 18 ng g⁻¹ for AsB, As(iii), DMA, MMA and As(v), respectively. This study allowed the determination of As species in seafood after culinary treatments, thus offering additional information about the behaviour of species during cooking.
This fit-for-purpose method was designed in response to recent and proposed food standards, both international and national, that limit inorganic arsenic rather than total, organic, or individual arsenic species such as arsenite (AsIII) and arsenate (AsV). In this method, AsIII is intentionally oxidized to AsV with H2O2 during sample preparation, converting all inorganic arsenic (the sum of AsIII and AsV) to the AsV form. Arsenic species were separated in less than 2 minutes using a short, narrow bore, 5 μm chromatography column. This analysis time is 10× faster than the current FDA regulatory method. The use of O2 reaction gas with inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ with MS/MS capability) avoided spectral interferences and dramatically increased sensitivity, allowing for low volume injections. The small injection volume and modified mobile phase composition mitigate non-spectral interferences such as carbon enhanced ionization. Furthermore, the shortened analysis time significantly increases sample throughput. Validation data from two laboratories demonstrate the method's accuracy and reproducibility of both wine and rice matrices in a single analytical batch.
This work reviews the operating principles of ICP-tandem mass spectrometry (ICP-MS/MS) and the key applications reported on since the introduction of the technique in 2012. The main differences between single quadrupole ICP-MS and ICP-MS/MS are elucidated and the tools available for method development are addressed. Examples of real-life applications are given to demonstrate the capabilities of this novel setup in the context of elemental, speciation and isotopic analysis. Attention has been paid to the different approaches (on-mass and mass-shift) allowing interference-free conditions to be obtained.
Human and ecosystem health concerns for arsenic (As) in the lower Athabasca River downstream of Athabasca Bituminous Sands (ABS) mining (Alberta, Canada) prompted an investigation to determine its forms in surface and groundwater upstream and downstream of industry. Dissolved As species, together with total and particulate As, were used to evaluate the potential bioavailability of As in water as well as to decipher inputs from natural geological processes and ABS mining and upgrading activities. Water samples were collected from the river in October at 13 locations in 2014 and 19 locations in 2015, spanning up to 125 km. Additional samples were collected from groundwater, tributaries and springs. “Dissolved” (<0.45 μm) As was consistently low in the Athabasca River (average 0.37 ± 0.01 and 0.34 ± 0.01 μg L⁻¹ in 2014 and 2015, respectively) as well as tributaries and springs (<1 μg L⁻¹), with As(V) as the predominant form. The average total As concentration was higher in 2014 (12.7 ± 2.8 μg L⁻¹) than 2015 (3.3 ± 0.65 μg L⁻¹) with nearly all As associated with suspended solids (>0.45 μm). In 2014, when total As concentrations were greater, a significant correlation (p < 0.05) was observed with thorium in particles > 0.45 μm, suggesting that mineral material is an important source of As. Naturally saline groundwater contained low dissolved As (<2 μg L⁻¹) and did not appear to be a significant source to the river. Arsenic in shallow groundwater near a tailings pond exceeded 50 μg L⁻¹ predominantly as As(III) warranting further investigation.
A rapid dilute-and-shoot procedure was described for the ultra-trace determination of Li, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Tl, Pb and U in honey by collision/reaction cell inductively coupled plasma mass spectrometry (CRC-ICP-MS). The aerosol dilution technique was found effective in obtaining a better tolerance to the sample matrix, allowing the use of aqueous standards in the analysis. Some instrumental parameters such as the collision gas flow rate, aerosol dilution rate and sampling depth were optimized for reliable determination of elements in the presence of chloride, especially for Cr and As which are severely affected by carbon and chloride-based polyatomic interferents. The limit of detection (0.01-2.9 ng g-1) and precision (< 3.3%) values were excellent. The main advantages of the method are the elimination of thermal digestion and aqueous dilution steps in sample preparation, and considerable reduction in reagent consumption and environmental waste. The results showed the applicability of the method in routine single-run multi-element analysis of various honey types (chestnut, multi-floral and sun flower).
Small selenium (Se) species play a major role in the metabolism, excretion and dietary supply of the essential trace element selenium. Human cells provide a valuable tool for investigating currently unresolved issues on the cellular mechanisms of Se toxicity and metabolism. In this study, we developed two isotope dilution inductively coupled plasma tandem-mass spectrometry based methods and applied them to human hepatoma cells (HepG2) in order to quantitatively elucidate total cellular Se concentrations and cellular Se species transformations in relation to the cytotoxic effects of four small organic Se species. Species- and incubation time-dependent results were obtained: the two major urinary excretion metabolites trimethylselenonium (TMSe) and methyl-2-acetamido-2-deoxy-1-seleno-β-d-galactopyranoside (SeSugar 1) were taken up by the HepG2 cells in an unmodified manner and did not considerably contribute to the Se pool. In contrast, Se-methylselenocysteine (MeSeCys) and selenomethionine (SeMet) were taken up in higher amounts, they were largely incorporated by the cells (most likely into proteins) and metabolized to other small Se species. Two new metabolites of MeSeCys, namely γ-glutamyl-Se-methylselenocysteine and Se-methylselenoglutathione, were identified by means of HPLC-electrospray-ionization-Orbitrap-MS. They are certainly involved in the (de-)toxification modes of Se metabolism and require further investigation.
Ar⁺ related product ions in an octopole reaction cell (ORC) were observed with an inductively coupled plasma tandem quadrupole mass spectrometer (ICP-QMS/QMS). In order to simplify the ion composition of the plasma, the carrier gas was directly connected to the torch injector, i.e. without introduction of the sample solution. The m/z of the first QMS was set to 40 permitting the passage of ⁴⁰Ar⁺. Isotope enriched oxygen gas (¹⁸O2) was used as the reaction gas in order to separate the spectra of O3⁺ and Ar2O²⁺. The intensities of the ions produced in the ORC were measured by the second QMS. As the products of the reactions among ⁴⁰Ar⁺ ions and ¹⁸O2 molecules in the ORC, the following ions were observed: ¹⁸O⁺¹⁸O2⁺¹⁸O3⁺¹⁸O4⁺⁴⁰Ar¹⁸O⁺⁴⁰Ar¹⁸O²⁺⁴⁰Ar2¹⁸O²⁺, and ⁴⁰Ar¹⁸O2²⁺. At a reaction gas flow rate of 0.3 mL min⁻¹, the ionic species with the highest signal intensity was ¹⁸O2⁺, followed by ⁴⁰Ar⁺ and ¹⁸O⁺. The maximum signal intensities of different product ions were obtained at different flow rates of the reaction gas. A lower flow rate of the reaction gas benefited the production of ⁴⁰Ar¹⁸O⁺ and ¹⁸O3⁺, while a higher flow rate of the reaction gas benefited the production of ⁴⁰Ar¹⁸O²⁺ and ⁴⁰Ar2¹⁸O²⁺. The maximum transfer efficiency from ⁴⁰Ar⁺ to the resulting ionic species was 91%, 2.0%, and 0.12% for ¹⁸O2⁺¹⁸O⁺, and ⁴⁰Ar¹⁸O⁺, respectively. The maximum transfer efficiency to the other investigated ionic species was less than 0.023%. By using ¹⁸O2 as the reaction gas, the mechanisms of ⁴⁰Ar⁺ resulted ionic species interfering with the measurement of ³²S¹⁶O⁺ were confirmed. The results showed that the contributions of ¹⁶O3⁺ and ⁴⁰Ar2O²⁺ were almost equivalent to each other.
In this study, a reliable method based on the combination of ion molecule reaction ICP-MS and addition of a CH4 plasma modifier technique was established for the direct determination of Se in Ca-rich groundwater samples. The ⁸⁰Se⁺ was oxidized to ⁸⁰Se¹⁶O⁺ by O2, and detected at m/z 96. Under the optimized conditions (O2 flow rate = 0.6 mL min⁻¹ and Rpq = 0.35), the new interferences of ⁹⁶Mo⁺ and ⁹⁶Zr⁺ could be oxidized to ⁹⁶Mo¹⁶O⁺ and ⁹⁶Zr¹⁶O⁺, and reduced by up to 300-fold and 457-fold. The poor sensitivity of ⁸⁰Se¹⁶O⁺ was increased 3.6-fold by introduced 2 mL min⁻¹ CH4 modifier to the ICP plasma. And a limit of quantification (LOQ, 10δ) of 0.06 μg L⁻¹ was obtained. The accuracy of proposed method was validated by analysis of certified reference materials of trace elements in water (SRM 1643e) and trace elements in natural water (SRM 1640a), and the determined values were in good agreement with the certified values. The proposed method was also successfully applied for the determination of trace Se in Ca-rich groundwater samples, and the spiked recoveries was in the range of 90.0%-103%.
Measurement of selenium in serum is an important clinical biomarker of nutritional status. The presence of gadolinium (Gd) in samples following administration of the contrast agents used for magnetic resonance imaging (MRI) results in a significant positive bias when using quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS).
Three instrumental set-ups were assessed: standard mode with no collision gas and collision cell mode with either a hydrogen:helium mixture or hydrogen. The effect of Gd on the selenium (Se) signal was assessed using external quality assurance (EQA) specimens and internal quality control (IQC) materials, both unspiked and spiked with Gd. Serum previously shown to contain high concentrations of Gd-containing contrast agents were also analysed.
Recoveries of Se in the spiked compared to the unspiked samples were: between 500% and 1300% using standard mode; 100% and 29,000% using collision cell mode with hydrogen:helium mixture; and between 99% and 103% using hydrogen. The use of H2 in the collision cell provided accurate results, indicating that the charge exchange reaction (CER) of Gd(2+) with H2 removes this interference. Analysis of patient serum known to contain the Gd contrast agent using the method gave results within the selenium reference range (adults 0.89-1.65 µmol/L). The presence of Gd, as low as 0.2 mg/L, in serum samples causes a positive interference on the measurement of Se by ICP-MS.
Using a CER mode with pure H2 in the collision cell it was possible to fully remove the interference due to Gd(2+) from the signal for Se.
Contaminated food through dietary intake has become the main potential risk impacts on human health. This study investigated concentrations of rare earth elements (REEs) in soil, vegetables, human hair and blood, and assessed human health risk through vegetables consumption in the vicinity of a large-scale mining area located in Hetian Town of Changting County, Fujian Province, Southeast China. The results of the study included the following mean concentrations for total and bio-available REEs of 242.92±68.98 (135.85-327.56)μgg(-1) and 118.59±38.49 (57.89-158.96)μgg(-1) dry weight (dw) in agricultural soil, respectively, and total REEs of 3.58±5.28 (0.07-64.42)μgg(-1) dw in vegetable samples. Concentrations of total REEs in blood and hair collected from the local residents ranged from 424.76 to 1274.80μgL(-1) with an average of 689.74±254.25μgL(-1) and from 0.06 to 1.59μgg(-1) with an average of 0.48±0.59μgg(-1) of the study, respectively. In addition, a significant correlation was observed between REEs in blood and corresponding soil samples (R(2)=0.6556, p<0.05), however there was no correlation between REEs in hair and corresponding soils (p>0.05). Mean concentrations of REEs of 2.85 (0.59-10.24)μgL(-1) in well water from the local households was 53-fold than that in the drinking water of Fuzhou city (0.054μgL(-1)). The health risk assessment indicated that vegetable consumption would not result in exceeding the safe values of estimate daily intake (EDI) REEs (100-110μgkg(-1)d(-1)) for adults and children, but attention should be paid to monitoring human beings health in such rare earth mining areas due to long-term exposure to high dose REEs from food consumptions.
Rice can be a major source of inorganic arsenic (Asi) for many sub-populations. Rice products are also used as ingredients in prepared foods, some of which may not be obviously rice based. Organic brown rice syrup (OBRS) is used as a sweetener in organic food products as an alternative to high-fructose corn syrup. We hypothesized that OBRS introduces As into these products.
We determined the concentration and speciation of As in commercially available brown rice syrups and in products containing OBRS, including toddler formula, cereal/energy bars, and high-energy foods used by endurance athletes.
We used inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography coupled to ICP-MS to determine total As (Astotal) concentrations and As speciation in products purchased via the Internet or in stores in the Hanover, New Hampshire, area.Discussion: We found that OBRS can contain high concentrations of Asi and dimethyl-arsenate (DMA). An "organic" toddler milk formula containing OBRS as the primary ingredient had Astotal concentrations up to six times the U.S. Environmental Protection Agency safe drinking water limit. Cereal bars and high-energy foods containing OBRS also had higher As concentrations than equivalent products that did not contain OBRS. Asi was the main As species in most food products tested in this study.
There are currently no U.S. regulations applicable to As in food, but our findings suggest that the OBRS products we evaluated may introduce significant concentrations of Asi into an individual's diet. Thus, we conclude that there is an urgent need for regulatory limits on As in food.
There are three major production bases of navel oranges in China, including Southern Jiangxi Province, Southern Hunan Province, and the Three Gorges District of the Yangtze River. Southern Jiangxi and Southern Hunan are also famous for rare earth elements that are ionic, making them easily passed from soil to plants and fruits. To test the relative enrichment of rare earth elements in navel oranges from these production sites, ICP-MS analysis was performed following a microwave digestion procedure. The concentrations of La, Ce, Pr, and Nd in navel orange peels from Southern Jiangxi and Southern Hunan (1.26–1.86 µg g−1) were much higher than results from the Three Gorges (0.23–0.46 µg g−1). Moreover, yttrium is relatively enriched (0.25–0.29 µg g−1) in navel orange peels from Southern Jiangxi at concentrations almost twice that from Southern Hunan (0.15 µg g−1). The various concentrations and distribution of rare earth elements offers the possibility of traceability and authentication of navel oranges. Meanwhile, navel orange peels from Southern Jiangxi posed no risk in consumption, based on the maximum limit level (≤0.7 µg g−1, wet weight) of rare earth elements in food issued in China (GB 2762-2005).
A quick and accurate method was devised to determine Se, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr and Zn in Se-rich rice samples by microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS). Spectral interferences on Se were eliminated using methane as a reaction gas in the dynamic reaction cell (DRC). Rhodium was used as an internal standard to compensate for sample matrix effects. A rice-certified reference material (CRM) (GBW 10010) was used to verify the accuracy of the method. The method detection limits were 0.001-0.03mg/kg, analyte recoveries were 85-108% and precisions (RSDs) ranged from 2.1% to 5.8%. Correlation analysis showed that the Se concentrations in the Se-rich rice samples correlated well with the Cu concentrations (r=0.53, p<0.05).
Due to the toxicity of inorganic arsenic (iAs) only iAs needs to be monitored in food and feedstuff. This demands the development of easy and quick analytical methods to screen large number of samples. This work focuses on hydride generation (HG) coupled with an ICP-MS as an arsenic detector where the HG is added as a selective step to determine iAs in the gaseous phase while organically bound As remains in the solution. iAs forms volatile arsine species with high efficiency when treated with NaBH4 at acidic conditions, whereas most other organoarsenic compounds do not form any or only less volatile arsines. Additionally, using high concentrations of HCl further reduces the production of the less volatile arsines and iAs is almost exclusively volatilized, therefore enabling to measure iAs without a prior step of species separation using chromatography. Here, we coupled a commercially available HG system to an ICP-MS and optimised for determination of iAs in rice and samples of marine origin using different acid concentrations, wet and dry plasma conditions and different reaction gas modes. Comparing this method to conventional HPLC-ICP-MS, no statistical difference in iAs concentration was found and comparable limits of detections were achieved using less than ½ the instrument time.
Direct determination of ng g− 1 level of selenium by ICP-MS is complicated because of the presence of serious spectral interferences, and the high first ionization energy of Se (9.75 eV) also results in low analytical sensitivity. In this study, a reliable method for accurate determination of Se in biological samples using CH4-Ar mixed plasma-DRC-MS was evaluated. The predominant interfering 40Ar2+ (from ion source) on the most abundant 80Se isotope was successfully eliminated by the charge transfer reaction using methane as DRC gas. The minor interferences of oxide or hydroxides ions (64Zn16O+, 64Ni16O+ and 63Cu16OH+) and double charged ions (159Tb2 +, 160,161Dy2 + and 160Gd2 +) originating from sample matrix were decreased down to 50% using CH4-Ar mixed gas plasma instead of the conversional pure Ar-ICP. Meanwhile, the poor sensitivity of Se+ was improved by a factor of 3 due to the carbon-enhancement effect in CH4-Ar mixed gas plasma. In addition, to avoid the interference 79BrH+ on 80Se+, an elaborate evaporation procedure was used to remove the Br from the digestion solution. The proposed method was applied to direct determination of Se in fifty biologically related SRMs. Our results showed that the values of most SRMs were found to agree well with the certified or recommended values. This method has great potential for the determination of trace or trace level of Se in various biological samples.
An inductively coupled plasma spectrometer (ICP-MS) equipped with a dynamic reaction cell (DRC) was used for determining Se in plant samples. A study was made of the ways of removing polyatomic interferences that affect the determination of the most abundant isotopes of selenium, using CH4 or, alternatively, NH3 as a reaction gas. We optimized the efficiency of the bandpass tuning and the cell gas flow rate for suppressing potentially interfering product ions formed by ion–molecule reactions in the dynamic reaction cell of an inductively coupled plasma mass spectrometer. 115In+ was selected as an internal standard for determining Se by DRCICP-MS. We monitored the rate of reaction between 115In+ and CH4 or NH3, and the product ions created from reactions between In+ and CH4 or NH3. The trueness of the analytical results was assessed by the use of CRMs for Se in plants. The Se experimental results obtained by DRCICP-MS and by conventional ICP-MS methods were compared with certified values. The values obtained by DRCICP-MS at m/z 78 with NH3 as the reaction gas were in good agreement with all analysed reference materials at an RPq value of 0.75, zero RPa and cell gas flow rate 0.8 mL min−1. The use of ammonia instead of methane was more appropriate for determining Se in plant samples. Higher reaction efficiency was achieved for suppressing the interferences of double charge ions of lanthanides, and, in addition, determining 80Se+ with CH4 as the reaction gas in plant material with a higher Br content, than in the certified reference material NIST Tomato Leaves 1573a (1300 ng g−1 Br), which suffers from strong interference from 1H79Br+.
Mass interferences, caused by atomic or polyatomic species and having the same mass/charge ratio of the analyte, can be a severe limit for a reliable assay of trace and ultratrace elements by ICP-MS. The DRC™ technology uses a reaction gas to overcome these interferences. Reactions of charge exchange, atom transfer, adduct formation, condensation and analyte association/condensation are the main mechanisms. Interfering ions tend to react with the gas exothermally, while, the analyte reacts endothermally. Selecting the most appropriate reaction gas in DRC-ICP-MS is the very critical point for the determination of strongly interfered elements. A careful evaluation of the reaction mechanisms and the chemistry involved are required. The DRC allows the use of different gases, among them, ammonia (NH(3)), methane (CH(4)), hydrogen (H(2)) and oxygen (O(2)) are the most known, but there are other potentially useful gases like nitrous oxide (N(2)O), nitrogen oxide (NO), carbon dioxide (CO(2)), fluoromethane (CH(3)F), sulphur hexafluoride (SF(6)) and carbon disulfide (CS(2)). This paper provides a review on the analytical challenges for a reliable assay of As, Cr, Se and V by DRC-ICP-MS and illustrates different approaches and mechanisms involved in the analysis of polymers, biological fluids (serum, urine and whole blood), rock, soil and particulate matter.
Direct determination of trace arsenic in high chlorine food samples by ICP-MS is complicated by the presence of ArCl(+) interferences, and the high first ionization energy of As (9.81 eV) also results in low analytical sensitivity in ICP-MS. In this work, two strategies based on ion-molecule reactions were successfully used to eliminate ArCl spectral interference in a dynamic reaction cell (DRC). The interference ion ((40)Ar(35)Cl(+)) was directly removed by the reaction with methane gas, and the background signal was reduced by up to 100-fold at m/z 75. Alternatively, by using molecule oxygen as the reaction gas, (75)As(+) was effectively converted to (75)As(16)O(+) that could be detected at m/z 91 where the background is low. The poor signal intensity of As or AsO was improved 3-4 times by addition of 4% methanol in the analyzed solutions. The limit of quantitation (LOQ) for (75)As (CH(4)-DRC method) and (75)As(16)O (O(2)-DRC method) was 0.8 and 0.3 ng g(-1) and the analytical results of seaweed and yellow croaker standard reference materials were in good agreement with the certified values. As the routine arsenic monitoring method in our laboratory, it was applied to the accuracy determination of 119 high chlorine food samples from eight different markets of Beijing.
Public health policy for arsenic needs to better reflect the ability to detect the risk(s).
Reliable determination of arsine (AsH(3)) in gases is of great importance due to stringent regulations associated with health, safety and environmental issues. It is, however, challenging for an analyst to determine trace airborne arsine concentrations without specifically designed collection procedures using adsorption, desorption, dissolution or impinging techniques. To circumvent such technical barrier, we have newly developed a direct analytical method, characterized by introduction of an arsine gas sample into stable plasma stream, followed by gas-phase oxidation of arsine with molecular oxygen in a dynamic reaction cell (DRC) equipped within the inductively coupled plasma-mass spectrometry (ICP/MS) system, followed by subsequent detection of AsO(+) ion. This preliminary work used trace arsine concentrations (161 microg m(-3), 322 microg m(-3), and 645 microg m(-3)) gravimetrically prepared in N(2) balance. The proposed method was optimized for the important experimental parameters such as the flow rates of the reaction gas, the arsine sample, and the carrier gas. This method was then validated by demonstrating good figure-of-merits including the low limit of detection (0.10 microg m(-3)), good linearity (r(2)>0.9915), low measurement uncertainty (0.66%), and high speed of analysis (<6 min). The proposed method is expected to be potentially applicable to the determination of arsine in real workplace air after appropriate modifications are made.
An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic and selenium. The arsenic and selenium species studied included arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), selenite [Se(IV)] and selenate [Se(VI)]. Gradient elution using (NH4)2CO3 and methanol at pH 9 allowed the chromatographic separation of all species in less than 12 min. Effluents from the IC column were delivered to the nebulization system of ICP-DRC-MS for the determination of arsenic and selenium. The potentially interfering 38Ar 40Ar+ and 40Ar 40Ar+ at the selenium masses m/z 78 and 80 were reduced in intensity by approximately 3 orders of magnitude by using 0.6 mL min(-1) CH4 as reactive cell gas in the DRC while an Rpq value of 0.3 was used. Meanwhile, arsenic was determined as the adduct ion 75As 12CHH+ at m/z 89, which is more sensitive than 75As. The limits of detection for arsenic and selenium were in the range of 0.002-0.01 ng mL(-1) and 0.01-0.02 ng mL(-1), respectively, based on peak height. The relative standard deviation of the peak areas for five injections of 5 ng mL(-1) As and Se mixture was in the range of 2-4%. The concentrations of arsenic and selenium species have been determined in urine samples collected locally. The major As and Se species in urines were AsB, DMA and probably selenosugar at concentration of 20-40, 15-19 and 17-31 ng mL(-1), respectively. The recoveries were in the range of 94-105% for all the determinations. This method has also been applied to determine various arsenic compounds in two fish samples. In this study, a simple and rapid microwave-assisted extraction method was used for the extraction of arsenic compounds from fish. The arsenic species were quantitatively leached with an 80% v/v methanol solution in a focused microwave field during a period of 5 min.
Many Bangladeshi suffer from arsenic-related health concerns. Most mitigation activities focus on identifying contaminated wells and reducing the amount of arsenic ingested from well water. Food as a source of arsenic exposure has been recently documented. The objectives of this study were to measure the main types of arsenic in commonly consumed foods in Bangladesh and estimate the average daily intake (ADI) of arsenic from food and water. Total, organic and inorganic, arsenic were measured in drinking water and in cooked rice and vegetables from Bangladeshi households. The mean total arsenic level in 46 rice samples was 358 μg/kg (range: 46 to 1110 μg/kg dry weight) and 333 μg/kg (range: 19 to 2334 μg/kg dry weight) in 39 vegetable samples. Inorganic arsenic calculated as arsenite and arsenate made up 87% of the total arsenic measured in rice, and 96% of the total arsenic in vegetables. Total arsenic in water ranged from 200 to 500 μg/L. Using individual, self-reported data on daily consumption of rice and drinking water the total arsenic ADI was 1176 μg (range: 419 to 2053 μg), 14% attributable to inorganic arsenic in cooked rice. The ADI is a conservative estimate; vegetable arsenic was not included due to limitations in self-reported daily consumption amounts. Given the arsenic levels measured in food and water and consumption of these items, cooked rice and vegetables are a substantial exposure pathway for inorganic arsenic. Intervention strategies must consider all sources of dietary arsenic intake.
Exposure to inorganic arsenic from rice: A global health issue?
- Y-G Zhu
- Williams Pn Meharg
- Aa
Zhu Y-G, Williams PN, Meharg AA. 2008. Exposure to inorganic arsenic from rice: A global health issue? Environmental Pollution 154:169-171
Guidance for industry. Arsenic in apple juice: Action level
- U S Fda
U.S.FDA. Guidance for industry. Arsenic in apple juice: Action level. 2013
Report of the eighth session of the codex committee on contaminants in foods
- Commission Ca
COMMISSION CA. 2014. Report of the eighth session of the codex committee on contaminants in foods. CL2014/11-CF. Geneva, Switzerland.
Arsenic in Apple Juice: Action level
- U S Fda
- Guidance
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Fda sets limit for arsenic in apple juice
Fda sets limit for arsenic in apple juice. Chemical & Engineering News. 2013; 91:21-21.
[Anonymous].
Codex Alimentarius Commission, Report of the Eighth Session of the Codex Committee on Contaminants in Foods
- Fao Joint
- Who Food Standards
- Program
Report of the eighth session of the codex committee on contaminants in foods. CL2014/11-CF
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COMMISSION, CA. Report of the eighth session of the codex committee on contaminants in foods.
CL2014/11-CF. Geneva, Switzerland: 2014.
Guidance for Industry
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