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Spectrophotometric Determination of Caffeine and Theophylline in Pure Alkaloids and Its Application in Pharmaceutical Formulations
Abstract
A novel-coupling reagent is used for the simple and sensitive spectrophotometric determination of caffeine (CF) and theophylline (TP) in pure or pharmaceutical formulations. The method is based on the oxidation of CF and TP with sodium metaperiodate in the presence of acetic acid, followed by coupling with 3-methyl 2-benzo thiazolinone hydrazone hydrochloride (MBTH), to produce a blue-colored product with a lambda(max) of 630 nm. The method is reproducible and has been applied for the determination of CF and TP in the tablets. The results are comparable to those obtained with the British pharmacopoeia (BP) method. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed method.
... Pengembangan metode analisis kafein secara kolorimetri dapat dilakukan melalui fabrikasi sensor kimia berbasis reagen kimia yang sensitif terhadap keberadaan kafein seperti senyawa fluorofor 8-hidroksipirena-1,3,6trisulfonat (HPTS) [14] menggunakan spektroflurometer serat optik [15] . Selain itu, sensor kafein berbasis kolorimetri ini dapat dikembangkan menggunakan oksidator NaIO4, asam asetat (CH3COOH) dan kromogen MBTH yang sebelumnya digunakan pada metode spektrofotometri [16], [17] . NaIO4 dapat mengoksidasi kafein pada suasana sedikit asam membentuk oksida kafein. ...
... Hasil analis kafein menggunakan sensor (metode skanometri) selanjutnya dibandingkan dengan hasil yang diperoleh dengan metode standar [16] (metode spektrofotometri) secara statistik mengunakan uji t bebas (independent t test). ...
... Reaksi oksidasi kafein oleh NaIO4 yang menghasilkan oksida-kafein yang bereaksi dengan kromogen MBTH pada suasana sedikit asam menjadi dasar mekanisme penginderaan sensor kafein [16] . Pada penambahan larutan kafein 300 ppm, sensor yang berwarna putih berubah menjadi biru seperti yang terlihat pada Gambar 2. ...
The caffeine chemical sensor was developed by co-immobilizing sodium periodate (NaIO4), 3-methyl-2-benzothiazolinone hydrazone (MBTH), and acetic acid (CH3COOH) onto paper by using an adsorption technique. The addition of caffeine solution could change the color of the sensor from white to pale blue which can be then captured by using a flatbed scanner and quantified by the ImageJ program, known as a scanometric technique. Method validation such as linearity, LOD, LOQ, precision, and accuracy of the sensor was done by using caffeine standards. The result of caffeine analysis using the developed chemical sensor-scanometric method agreed with that of the spectrophotometric method, suggesting that the developed sensor with scanometric technique can be used as an alternative method for caffeine assay in coffee samples.
... Caffeine is the main alkaloid found in many kinds of foods and drinks [1] and thus the determination of caffeine is required in food laboratories in order to inform the consumers about the characteristics and concentration. There are several methods proposed in the literature for the determination of caffeine in foods, based on ultraviolet UV -visible spectrophotometry [2], HPLC [3][4][5] or mass spectrometry [6]. ...
... Caffeine is found in various kinds of foods and drinks that we consume in daily life [1]. About 200 mg of caffeine contains pharmacological effect. ...
In this work a study was performed using UV/Vis spectrophotometer to determine the concentrations of caffeine in coffee, tea and chocolate milk available in local market in Riyadh, Saudi Arabia. Quantitative analysis was carried using dichloromethane as extracting solvent. Results showed that the minimum caffeine level was observed in the chocolate milk (16.38 ppm) and the highest caffeine content observes in coffee (32 ppm).
... The main objective of this study is to produce a quick and reproducible method for the routine, simultaneous analyses of CF, in food, drinks, and herbal products (1,(11)(12)(13)(14)(15)(16)(17)(18)(19)). ...
... This solution (0.2-10.0 µL) was injected daily under the same conditions and the results were used for the repeatability study. The solution was stored at room temperature (25 ± 2°C) in sunlight (1,3,7,12,18). ...
Many beverages such as soft drinks, coffee and tea contain the mild stimulant caffeine (C8H10N4O2). The caffeine content varies widely from about 100 μg/mL (100 ppm) in sodas to over 1000 μg/mL in certain types of coffee. For this reason the caffeine and the content in they need to be analyzed. A rapid and selective high-performance liquid chromatographic (HPLC) method is developed for the separation and determination of caffeine.
... Then, samples were transferred in a water bath at 60 • C for 10 min, and absorbance was recorded at 535 nm. Alkaloide contents were determined by the prescribed method of Singh and Sahu (2006). For this purpose 0.1 g of fresh leaf sample was homogenoized with 1 mL of methanol. ...
... Long-term sleeplessness, peptic ulcers, and elevated serum cholesterol are the main negative consequences of caffeine [34]. Numerous analytical methods were used for the assessment of CAFF in variable matrices like UV/Visible spectrophotometric methods like [35][36][37][38][39], partial least-squares algorithm (PLS) [40], chromatographic methods [41][42][43][44][45][46][47][48][49][50][51][52] and electrochemical methods [53][54][55][56]. Paracetamol (PAR) is N-(4-hydroxyphenyl) acetamide [6]. ...
Three green and facile spectrophotometric methods were developed for the assay of Petro® components; drotaverine HCl (DRT), caffeine (CAFF), and paracetamol (PAR). The three methods depend on measuring the absorbance of the studied drugs through their ethanolic solution. The first derivative spectrophotometry (FDS) at (Δλ = 10) were good parameters for DRT and CAFF resolution; DRT and CAFF could be well calibrated using FDS at 320 and 285 nm, respectively. PAR could be estimated at 308 nm utilizing the second derivative spectrophotometry (SDS). Method II relies on the double divisor ratio derivative spectroscopy (DDRDS). The first derivative was applied on each drug where they would be assayed at 309, 288, and 255 nm for DRT, CAFF, and PAR, respectively. Method III depends on the mean centering (MCR) technique. DRT, CAFF, and PAR could be determined at 309, 214, and 248 nm, respectively. The concentrations were rectilinear in the ranges of 2–20 µg/mL for DRT, 1.5–15 µg/mL for CAFF, and 2–40 µg/mL for PAR in double devisor and mean centering but PAR from 5 to 40 µg/mL in derivative method. Method validation was performed according to ICH guidelines assured by the agreement with the comparison method. In addition, greenness assessment of the proposed methods was investigated. The application of the proposed method was extended to analyse tablet dosage form and performing invitro dissolution testing.
... Its oxidation was investigated as a tool for spectrophotometric determination of theophylline concentration in pure or pharmaceutical formulations (Singh and Sah, 2006). The compound was oxidized with sodium metaperiodate in the presence of acetic acid and a blue-colored product with a λmax of 630nm was observed (Abe, et al., 2003). ...
The kinetic studies of the oxidation of theophylline by permanganate ion in aqueous acidic solution has been studied. One mole of theophylline was consumed by one mole of permanganate ion. The result showed first order dependence with respect to both theophylline and permanganate ion concentrations. The oxidation rate increased with increase in the concentration of H + and ionic strength of the reaction medium. The reaction was carried out at [MnO4-] = 2.0 x 10-4 mol dm-3 , [H + ] = 1.0 x 10-2 mol dm-3 , I = 0.5 mol dm-3 (NaSO4), λmax = 530nm and T = 24 ± 0.1 o C.. This conforms to the rate law:-d [MnO4-] /dt = (a + b [H + ])[TP][MnO4-], where a = 0.034 dm 3 mol-1 s-1 and b = 0.43 dm-3 mol-1 s-1. Spectroscopic and kinetic investigation depict that there was no intermediate formation prior to electron transfer. A plausible reaction mechanism consistent with the kinetic results is proposed. (
... The method by Singh and Sahu [49] was used to measure the total alkaloids contents. Plant material (0.1 g) was homogenized in 1 mL of methanol and then diluted with distilled water. ...
Milk thistle (Silybum marianum (L.)) is a wild medicinal herbal plant that is widely used in folk medicine due to its high content of secondary metabolites (SMs) and silymarin; however, the data regarding the response of milk thistle to salinity are still scarce and scanty. The present study evaluated the effect of salinity on a geographically diverse population of milk thistle and on the role of medium supplementation (MS) with ascorbic acid, thiourea, and moringa leaf extract in improving the SMs and growth-related attributes under salinity stress (SS). For germination, a 120 mM level of salinity was applied in the soil during the seedling stage. After salinity development, predetermined levels of the following compounds were used for MS: thiourea (250 µM), moringa leaf extract (3%), and ascorbic acid (500 µM). The data regarding growth attributes showed that SS impaired plant growth and development and increased SM production, including alkaloids, anthocyanin, and saponins. Moreover, ascorbic acid, followed by moringa leaf extract, was the most effective in improving growth by virtue of increased SMs, especially under salt stress conditions. The present study demonstrated that milk thistle could withstand moderate doses of SS, while MS improved all the growth parameters by increasing the accumulation of SMs.
... Consequently, therapeutic drug monitoring (TDM) of THO is highly essential. A plethora of techniques has been employed to date for monitoring THO levels, such as various types of chromatography [31][32][33][34], capillary electrophoresis [35], spectrophotometry [36,37], immunoassays [38][39][40], and differential derivative spectroscopy [41,42]. Many of these techniques are very complicated and necessitate time-consuming operations and the expertise of skilled technicians. ...
This work focuses on a carbon-based imprinted polymer composite, employed as a molecular recognition and sensing interface in fabricating a disposable electrochemical sensor. The carbon paste electrode was made of a molecularly imprinted polymer comprising a copolymer of methacrylic acid as the functional monomer and blended crosslinking monomers of N,N-methylenebisacrylamide,
and ethylene glycol dimethacrylate, with theophylline as the template. The analytical properties of the proposed theophylline sensor were investigated, and the findings revealed an increase in differential pulse voltammetric current compared to the non-imprinted electrode. Under optimized conditions, the sensor has shown high sensitivity, high selectivity, lower detection limit (2.5 μg/mL), and satisfactory long-term stability. Further, the sensor was tested in whole bovine blood and validated without any matrix effect and cross-reactivity. Additionally, chronoamperometry of the sensor chip supported a rapid determination of THO with a short response time of 3 s. This carbon-paste electrode is highly specific for theophylline and may be applied as a drug sensor for clinical use.
... Techniques including ion chromatography (Chen et al., 1998), high-performance liquid chromatography (HPLC) (Sereshti et al., 2014), electrospray ionization ion mobility spectrometry (ESI-IMS) (Jafari et al., 2011), Ultra-High-Performance Liquid Chromatography-Mass Spectrometry (Aqel et al., 2019), and spectrophotometry (Singh and Sahu, 2006) have been reported for determi-nation of TP and CAF. However, these techniques require expensive instruments, skilled operators, large sample volume, tedious sample pretreatment procedures, and long analysis time (Filik et al., 2017;Shu et al., 2017). ...
This paper presents metal complex based polymer film modified electrode for simultaneous determination of caffeine, and theophylline. Potentiodynamic fabrication of poly(aquachlorobis(1,10– phenanthroline)cupper(II)iodidemonohydrate) modified glassy carbon electrode (poly(ACP2CuIH)/GCE) was verified using cyclic voltammetric and electrochemical impedance spectroscopic techniques. In contrast to the unmodified glassy carbon electrode, the poly(ACP2CuIH)/GCE in equi-molar mixture of theophylline and caffeine revealed sufficiently separated oxidative peaks with much enhanced peak current showing electrocatalytic property of the polymer film towards the oxidation of theophylline and caffeine. Under optimized solution pH and square wave voltammetric parameters, oxidative peak current response of poly(ACP2CuIH)/GCE showed linear dependence on the concentration of caffeine and theophylline in the concentration range 1.0-200.0 µM with limit of detection 8.92 × 10-3 µM for theophylline, and 1.02 × 10-2 µM for caffeine. Spike recovery in the range 95.4-101.0% for theophylline, and 98.9-101.4% for caffeine, interference recovery in the range 96.0-101.0 for theophylline, and 95.7-103.0 for caffeine, agreement of the detected amounts of theophylline and caffeine in tablet samples with the nominal values, and stability of the modified electrode all validated the developed method for simultaneous determination of theophylline and caffeine in wide range of real samples. The method was applied for simultaneous determination of both theophylline and caffeine in three tea brands (Black lion, Addis, and Wush wush), pharmaceutical tablet brands (Panadol extra, and Theodrine), and human blood serum samples making the method an excellent candidate.
... Alkaloid content was estimated using the described method of Singh and Sahu (2006). A 0.1 g plant sample was extracted in 1 mL of methanol, then samples were diluted with distilled water. 1 mL of extract was taken and 0.01 M sodium metaperiodate (SP1) and 0.5 mL acetic acid were added. ...
The aim of the present work was to evaluate the effect of different plant growth promoters (PGPs) such as ascorbic acid (500 μM), thiourea (250 μM) and moringa leaf extract (3%) to mitigate salinity stress (120 mM NaCl) in four different milk thistle [Silybum marianum (L.) Gaertn.] ecotypes from Faisalabad (FSD), Gujranwala (GUJ), Kallar Kahar (KK), and Quetta (QTA) under field conditions for two years (2017–2018). In the present study, oxidative stress indicators such as malondialdehyde (MDA) and hydrogen peroxide (H2O2) and activities of different antioxidant enzymes and levels of non-enzymatic antioxidants were significantly differed among ecotypes, salinity, and PGPs. Supplementation with ascorbic acid and moringa leaf extract improved antioxidant defense machinery during the acclimation process against salinity, and milk thistle ecotypes represent their background of ecological zones and inherent tendency to face and confronting stress with improving antioxidant levels to a significant extent in varying ways. Ecotypic variations showed that QTA ecotype Followed by FSD, GUJ, and KK had more antioxidant capacity, with minimum reactive oxygen species production. Interestingly, the correlation data revealed that MDA and H2O2 had a positive correlation with each other and showed a negative correlation with all the enzymatic and non-enzymatic antioxidants.
... Finally, the blue colour complex was measured at 630 nm in spectrophotometer and expressed in mg/g of dry extract by using caffeine as standard. 14 ...
Since prehistoric times Coccinia grandis has been used as traditional medicine for various diseases including diabetes, dyslipidemia, metabolic and digestive disorders. Although the rationality of efficacy as natural antioxidants with different bioactive compounds in Coccinia grandis against monosodium glutamate (MSG) induced hepato-cardiac damage remains to be disclosed. Six different solvent extracts of the leaves of Coccinia grandis were chosen to evaluate in vitro antioxidant and free radical (FR)-scavenging activity. Due to high antioxidant content and FR-scavenging property of ethanol extract of Coccinia grandis leaves (EECGL) and presence of different bioactive compounds in EECGL was further tested to evaluate in vivo hepato-protective and cardio-protective efficacy against MSG-induced anomalies. MSG-induced dyslipidemia, increased cell toxicity markers altered functional status and histopathological peculiarities of target organs were blunted by EECGL. Additionally, MSG incited increase level of interleukin (IL)-6, tumour necrosis factor (TNF)-α, IL-1β which activates nuclear factor kappa-B (NF-kB) guided inflammation via down regulation of IL-10; impaired redox-homeostasis subsequently promoted inflammation associated oxidative stress (OS) and increased vascular endothelial growth factor (VEGF) which provoked microvascular proliferation related cellular damage. On the contrary, increased lipid peroxidation and nitric oxide promotes reduced cell viability, deoxyribonucleic acid damage and apoptosis via activation of caspase 3. EECGL significantly reduced MSG-induced inflammation mediated OS and apoptosis via inhibition of pro-inflammatory factors and pro-apoptotic mediators to protect liver and heart. Therefore, it can be suggested that EECGL contributed competent scientific information to validate the demands for its use to treat MSG-induced hepato-cardiac OS mediated inflammation and apoptosis from natural origin.
... From the standard curve on the graph, unknown sample concentration was calculated. [15] ...
India is the second largest consumer of tobacco globally, and accounts for approximately one-sixth of the worlds' tobacco related deaths. The tobacco problem in India is peculiar, with the consumption of variety of smokeless and smoking forms. Unlike other members of the Solanaceae family, such as tomato and potato, which have uncontroversial nutritional role, tobacco plant carries in its leaf's quantities of alkaloids; Nicotine which acts as a stimulant. This present study investigates the physico-chemical and phytochemical parameters, and the biological activity of the stimulating compound present in the North Indian Tobacco product. Analysis was carried out through chromatographic techniques of TLC, GC-MS, UV and IR spectroscopy. The result of the findings shows that tobacco product contains Acetoin, an additive intoxicating compound which has similar effect as Ethanol intoxication with remarkable antioxidant activity.
... The literature contains many analytical procedures for determination of CAF in different matrices either alone or in combination with other drugs. It has been quantified using spectrophotometric [15], spectrofluorimetric [16], HPTLC [12,[17][18][19], and HPLC [10,[20][21][22] methods. Paracetamol (PAR), as shown in Figure 1, chemically named N-(4-hydroxyphenyl)acetamide, is analgesic and antipyretic agent [1,2]. ...
A novel ecofriendly, cost and time saving high performance thin layer chromatographic method was developed and validated for simultaneous determination of metoclopramide, ergotamine, caffeine and paracetamol in bulk and pharmaceutical formulation. The separation was carried out on silica gel plates, using ethyl acetate: ethanol: ammonia (9: 1: 0.1, by volume) as a developing system. Ultra violet detection was carried out at 272 nm. The resulting retention times were 0.15, 0.36, 0.49 and 0.74 for metoclopramide, ergotamine, caffeine, and paracetamol, respectively. The greenness profile assessment was achieved to the proposed method to evaluate its greenness characters to the environment with acceptable results. Validation parameters were checked according to International Conference of Harmonization guidelines to achieve the international requirements for quality control analysis of the proposed drugs.
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... Because of its high preconcentration factor, low cost, low consumption of solvent, simplicity and flexibility, SPE method is considered as the highly effective preconcentration method amongst the previous methods 6, 9,10 . In this study, we present a fast, simple and new method for determination of trace amount of theophylline in aqueous solutions using magnetic iron oxide nanoparticles which were coated by aluminum oxide and modified with palmitate as a solid phase extractor (P@AMIONPs). ...
A new, simple and fast solid-phase extraction method for separation and preconcentration of trace theophylline in aqueous solutions was developed using magnetite nanoparticles (MIONPs) coated with aluminium oxide (AMIONPs) and modified with palmitate (P) as an extractor (P@AMIONPs). It has shown that the developed method has a fast absorbent rate of the theophylline at room temperature. The parameters that affect the absorbent of theophylline in the aqueous solutions have been investigated such as the amount of magnetite nanoparticle, pH, standing time and the volume, concentration of desorption solution. The linear range, limit of quantification (LOQ) and limit of detection (LOD) for the determination of theophylline were 0.05-2.450 µg mL-1 , 0.05 µg. mL-1 and 0.032 (n=10) respectively. The PF (Preconcentration factor) obtained for the proposed method in 98% is 75. The intra-day and inter-day precisions were 2.1% and 3.6% (for 1.0 µg mL-1 , n=10). The relative standard deviation R.S.D for 1.0 µg mL-1 is 1.26 (n=10). The proposed method has been successfully applied for the determination of theophylline in the pharmaceutical preparations.
... Because of its high preconcentration factor, low cost, low consumption of solvent, simplicity and flexibility, SPE method is considered as the highly effective preconcentration method amongst the previous methods 6, 9,10 . In this study, we present a fast, simple and new method for determination of trace amount of theophylline in aqueous solutions using magnetic iron oxide nanoparticles which were coated by aluminum oxide and modified with palmitate as a solid phase extractor (P@AMIONPs). ...
A new, simple and fast solid-phase extraction method for separation and preconcentration of trace theophylline in aqueous solutions was developed using magnetite nanoparticles (MIONPs) coated with aluminium oxide (AMIONPs) and modified with palmitate (P) as an extractor (P@AMIONPs). It has shown that the developed method has a fast absorbent rate of the theophylline at room temperature. The parameters that affect the absorbent of theophylline in the aqueous solutions have been investigated such as the amount of magnetite nanoparticle, pH, standing time and the volume, concentration of desorption solution. The linear range, limit of quantification (LOQ) and limit of detection (LOD) for the determination of theophylline were 0.05-2.450 µg mL-1 , 0.05 µg. mL-1 and 0.032 (n=10) respectively. The PF (Preconcentration factor) obtained for the proposed method in 98% is 75. The intra-day and inter-day precisions were 2.1% and 3.6% (for 1.0 µg mL-1 , n=10). The relative standard deviation R.S.D for 1.0 µg mL-1 is 1.26 (n=10). The proposed method has been successfully applied for the determination of theophylline in the pharmaceutical preparations.
... Because of its high preconcentration factor, low cost, low consumption of solvent, simplicity and flexibility, SPE method is considered as the highly effective preconcentration method amongst the previous methods 6, 9,10 . In this study, we present a fast, simple and new method for determination of trace amount of theophylline in aqueous solutions using magnetic iron oxide nanoparticles which were coated by aluminum oxide and modified with palmitate as a solid phase extractor (P@AMIONPs). ...
... The alkaloids were estimated spectrophotometrically by the method of Singh and Sahu 2006 [14] , flavonoids were estimated by the method of Zhishen et al., 2010 [15] . Saponins, tannins, phenolic content and sterols were estimated by the methods of Obadoni and Ochuko 2001, Graham 1992, Singleton andRosi 1965) [16][17][18] . ...
The present study was performed to assess the presence of phytochemical constituents in aqueous and methanol extracts of rhizomes of Podophyllum hexandrum and to investigate their antibacterial activity. The estimation of phytochemical constituents in methanol proved to be effective solvent for the extraction of secondary metabolites from the rhizomes of Podophyllum hexandrum. Methanol extract exhibited significantly higher (p<0.05) amounts of secondary metabolites and antibacterial activity against the test organisms at 10mg/ml, 28.6 ±0.21 and 24.4±0.17 in comparison to standard antibiotics 19.8 ± 0.16 and 19.9 ± 0.21 and aqueous extract 17.9±0.22 and 18.3±0.18 respectively. The methanol extract also demonstrated higher zone of inhibition against bacteria from 8-11 mm while aqueous extract exhibited zone of inhibition from 8-10mm.
... A number of different analytical methods have been developed for the separation and/or determination of caffeine in various samples. UV/Vis spectrophotometry [4], thin-layer chromatography [5], ion chromatography [6], Fourier transform-Raman [7], high performance liquid chromatography [8,9], Fourier transform infrared spectrometry [10], capillary electrophoresis [11], electrospray ionization ion mobility spectrometry (ESI-IMS) [12] and gas chromatography-mass spectrometry (GC-MS) [13,14] are among these methods. In some of the methods mentioned, preconcentration and isolation of caffeine from the matrix is a requirement in order to increase sensitivity or reduce matrix interferences. ...
... Among the factors, level of caffeine (caffeine content) [18,19] is an important factor. There are several reports on health benefits or desirable physiological effects of caffeine in humans [20][21][22][23] if it is taken in moderate amounts (130-300 mg/day) [24]. However, it has adverse effects if taken in higher amounts (>400 mg/day) [24]. ...
Ethiopia is the home land of biodiversity of coffea arabica seeds. The major and most known coffee producing regions in the country are Oromiya and Southern Nations Nationalities and Peoples Region. The objective of this study was to determine the caffeine content of coffee bean samples obtained from coffee growing areasof Bale zone, Oromia region. The samples were collected from farmers' union that supplies coffee to Ethiopian Commodity Exchange (ECX) or exporters. The collected samples were roasted and powdered to facilitate the extraction. The powders were then boiled with water, filtered and subjected to liquid-liquid extraction using dichloromethane. The extracts were subjected to High Performance Liquid Chromatographic analysis. The results revealed that caffeine levels to be 1.31 ± 0.14% for Gololcha coffee, 1.32 ± 0.03% for Harena Buluk forest coffee, 1.33 ± 0.08% for Mena forest coffee, 1.34 ± 0.21% for Berbere coffee, 1.36 ± 0.02% for Harena Buluk cultivated coffee and 1.36 ± 0.16% for Mena cultivated coffee (on dry matter basis). The finding also showed that there are no significant differences in the caffeine contents of the coffee samples used in the study. Moreover, the caffeine contents were in the range of export standards of Ethiopia.
... Caffeine is found in various kinds of foods and drinks that we consume in daily life (Singh & Sahu, 2006). It causes various physiological effects such as relaxation of bronchial muscle, stimulation of the central nervous system, gastric acid secretion and dieresis Bolton and Null (1981). ...
... There are reports of several techniques for the determination of XT, TP and CF including chromatography [5,10,11], spectrophotometry [12] and electrochemical (EC) methods [1-4, 6,7]. Of these, EC methods are comparatively simple, low-priced and requires very less chemical treatment thereby providing rapid analysis. ...
Xanthine and its methyl derivatives, theophylline and caffeine are purines which find important roles in biological systems. The simultaneous voltammetric behaviour of these purines has been studied on a glassy carbon electrode modified with an electropolymerised film of para amino benzene sulfonic acid. Well defined and well separated peaks were obtained for the oxidation of xanthine, theophylline and caffeine on the polymer modified electrode in the square wave mode. The experimental requirements to obtain the best results for individual as well as simultaneous determination were optimised. The signal for the electro-oxidation was found to be free of interferences from each other in the range 0.9 – 100 μM in the case of xanthine and from 10–100 μM in the case of theophylline and caffeine with detection limits 0.35 μM, 7.02 μM and 11.95 μM respectively. The simultaneous determination of uric acid, the final metabolic product of xanthine oxidation in biological systems could also be accomplished along with xanthine, theophylline and caffeine atphysiological pH. The mechanistic aspects of the electro-oxidation on the polymer modified electrode was also studied using linear sweep voltammetry. Chronoamperometry was employed to determine the diffusion coefficient of these xanthines. The developed sensor has been successfully demonstrated to be suitable for the determination of these compounds in real samples without much pre-treatment.
... In this context, quantitative analysis and quality control of commercial drinks require new powerful analytical methods giving reliable, precise, and accurate results with short runtime and low cost of analysis. Several analytical methods including spectrophotometry for CAF [1,2] and AA [3], high-performance liquid chromatography for CAF [4e16] and AA [17e22], liquid chromatographyemass spectrometry for CAF [23] and AA [24], voltammetry for CAF [25e27] and AA [28e32], Fourier transform infrared spectrophotometry for CAF [33e35] and AA [36], chemiluminescence for CAF [37], gas chromatographyemass spectrometry for CAF [38], ion chromatography for CAF [39], capillary electrophoresis for CAF [40], and ultra-highperformance liquid chromatography for CAF [41] and AA [42] have been reported for the analysis of the related compounds in drinks and pharmaceuticals. A literature survey revealed that there was no report about the simultaneous estimation of AA and CAF in the mentioned samples. ...
A new reversed-phase ultraperformance liquid chromatography method with a photodiode array detector was developed for the quantification of ascorbic acid (AA) and caffeine (CAF) in 11 different commercial drinks consisting of one energy drink and 10 ice tea drinks. Separation of the analyzed AA and CAF with an internal standard, caffeic acid, was performed on a Waters BEH C18 column (100 mm × 2.1 mm, 1.7 μm i.d.), using a mobile phase consisting of acetonitrile and 0.2M H3PO4 (11:89, v/v) with a flow rate of 0.25 mL/min and an injection volume of 1.0 μL. Calibration graphs for AA and CAF were computed from the peak area ratio of AA/internal standard and CAF/internal standard detected at 244.0 nm and 273.6 nm, respectively. The developed reversed-phase ultraperformance liquid chromatography method was validated by analyzing standard addition samples. The proposed reversed-phase ultraperformance liquid chromatography method gave us successful results for the quantitative analysis of commercial drinks containing AA and CAF substances.
... Determination of caff eine content. The amount of caff eine in the coff ee extracts was determined spectrophotometrically according to the method described by Singh and Sahu (2006). A standard curve was prepared in the concentration range 0.02-0.2 ...
Background. Coffee is important source of natural antioxidants in the diet, such as phenolic compounds, alkaloids, mainly caffeine, diterpenes (cafestol and kahweol) and Maillard reaction products formed during roasting.
Material and methods. In aqueous and methanolic extracts of coff ee (Coffea arabica L.) roasted using traditional techniques from Brazil (B), Colombia (C), Ethiopia (E), Kenya (K) and coffee roasted using an industrial technique from Brazil (T), the phenolic and caffeine content as well as antioxidant properties were determined.
Results. Comparing the results from water and methanolic extracts it should be noted that the highest amount of phenolics was determined for a methanolic extract of coff ee roasted using the industrial technique (650.96 mg GAE/g DW) and a water extract of Kenya coffee (461.63 mg GAE/g DW). Caffeine content was on average two times higher in all methanolic extracts than in water extracts. The radical scavenging activity of aqueous extracts was found to be higher than methanolic extracts. The highest antioxidant scavenging activity was determined for C (EC50 = 1.16 mg DW/ml) and E (EC50 = 1.3 mg DW/ml) water extracts. Compared to water extracts methanolic extracts showed signifi cantly higher reducing power, ability to chelate Fe²⁺, inhibition of linoleic acid peroxidation and inhibition of lipoxygenase.
Conclusions. This study demonstrated that the methanolic extracts obtained from different types of coffee exhibit potential anti-infl ammatory and antioxidant properties. The highest antioxidant activity was shown by traditionally roasted coffees from Colombia and Ethiopia
... Several modern analytical methods have been evolved for the determination of CAF (Zou and Li 2006;Verenitch et al. 2006;Khorrami and Rashidpur 2012;Gardinali and Zhao 2007;Al-Othman et al. 2012;Hadad et al. 2012;Rostagno et al. 2011;Injac et al. 2008;Singh and Sahu 2006;Jin et al. 2000) and VAN (Farthing et al. 1999;Ainscough and Brodie 1990;De Jager et al. 2008;Sostaric et al. 2000;Sobolev 2001;Waliszewski et al. 2006;Boyce et al. 2003;Ohashi et al. 2007;Sinha et al. 2007;Sanchez et al. 1990) such as spectrophotometry, chromatography (i.e., gas and liquid), and capillary electrophoresis (CE). These techniques are time-consuming, pricey, and also need qualified operators and sophisticated instrumentations. ...
Poly(alizarin red S) conducting polymer was prepared on glassy carbon electrode (GCE) surfaces, and the functionalized electrode was used for the simultaneous determination of caffeine (CAF) and vanillin (VAN). The peak potential separation for caffeine and vanillin was about 600 mV in 0.1 M acetate buffer solution (pH 4.0). The peak currents for the oxidation of both CAF and VAN are increased at poly(alizarin red S) (poly(ARS)) functionalized electrode, which makes it suitable for simultaneous detection of these compounds. The square wave voltanmmetry peak current of VAN was linear with the concentration of VAN from 0.5 to 250 μM in the presence of 250 μM CAF. The detection limit of VAN was found to be 0.06 μM in the presence of CAF. At the same time, the peak current of CAF was linear with the concentration of CAF from 10 to 450 μM with a detection limit of 0.8 μM (S/N = 3) in the presence of 30 μM VAN. The poly(ARS) functionalized GCE has good reproducibility and high stability. In addition, the proposed method was successfully applied to determine CAF and VAN in energy drink and vanilla sugar samples with good results.
... Analytical methods for caffeine detection are available and include, HPLC-MS [5][6][7], thin layer chromatography [8], ELISA [9], spectrophotometry [10,11], quartz crystal microbalance [12], piezoelectric quartz sensor [13], acoustic wave sensor [14], electrochemical differential pulse voltammetry [15], CV-EIS [16,17], electrochemical analysis by using molecularly imprinted polymers [18], gas chromatography [19] flow injection analysis (FIA) with multiple pulse amperometric detection [20], FIA -FT-IR [21] and colorimetric [22] methods. However, these methods suffer from several disadvantages like, long time for analysis, tedious sample clean up procedures, electrode fouling, high cross reactivity, low sensitivity etc. Fluorescence based chemo-sensor probes are attractive due to their high selectivity, simplicity, real-time spatial imaging and non-destructive nature [23]. ...
The study describes a simple and sensitive fluorometric sensor based on the enhancement of fluorescence intensity of Europium ion (Eu(3+)) - tetracycline (TC) charge transfer complex on addition of caffeine. The Eu(3+)-TC ternary complex has a characteristic emission peak at 615 nm (λex = 375 nm), the intensity of which increases with increase in concentration of caffeine. The caffeine sensor assay was found to be linear in the range of 0.0515 mM to 51.5 mM. The limit of detection and quantification were found to be 0.0515 mM and 0.382 mM, respectively. A caffeine recovery of 90 to 110 % in biological samples (serum and urine) indicated minimal interference by commonly present excipients in the samples. Rosenthal plots to calculate the binding capacity of caffeine with the Eu(3+)- TC complex revealed an association constant (K) of 238 x 10(3) L/mol and binding number (N) of 1.9. Bland-Altman plot comparing the developed assay and HPLC showed good agreement between values obtained by both the methods. The proposed fluorescent chemical sensor is a rapid and convenient method to determine caffeine with excellent recovery and low detection limit. The probable reaction mechanism for the formation of the turn on fluorescent probe enhancer is discussed.
... But theophylline has a narrow therapeutic index and is toxic at higher concentration that can lead to permanent neurological damages making its determination a key factor in drug administration [5]. Analytical methods developed for this such as high-performance liquid chromatography [6,7], spectrophotometry [8,9], gas chromatography coupled mass spectrometry [10], immunoassay [11,12], and capillary electrophoresis [13], involved tedious, time-consuming and laborious pretreatment steps, complicated and expensive instruments, skilled operators etc. [14]. But the electrochemical methods adopted for the detection of theophylline were reported for their simplicity, high sensitivity, low-cost instrumentation and easy operation [14]. ...
Theophylline is an inexpensive drug employed in asthma and chronic obstructive pulmonary disorder medications and is toxic at higher concentration. The development of a molecularly imprinted polymer based theophylline electrochemical sensor on glassy carbon electrode by the electropolymerization of 4-amino-5-hydroxy-2.7-naphthalenedisulfonic acid is being discussed in this work. The MIP modification enhances the theophylline recognition ability and the electron transfer kinetics of the bare electrode. The parameters, controlling the performance of the imprinted polymer based sensor, like number of electropolymerization cycles, composition of the pre-polymerization mixture, pH and immersion time were investigated and optimized. The interaction energy and the most stable conformation of the template–monomer complex in the pre-polymerization mixture were determined computationally using ab initio calculations based on density functional theory. The amperometric measurements showed that the developed sensor has a method detection limit of 0.32 μM for the dynamic range of 0.4 to 17 μM, at optimized conditions. The transducer possesses appreciable selectivity in the presence of structurally similar interferents such as theobromine, caffeine and doxofylline. The developed sensor showed remarkable stability and reproducibility and was also successfully employed in theophylline detection from commercially available tablets.
... AP is an effective and widely used antipyretic and analgesic drug [1]. TP is one of the most commonly used medications for the treatment of the symptoms of chronic asthma [2]. CF is used therapeutically in combination with nonsteroidal antiinflammatory drugs in analgesic formulations [3]. ...
The authors describe a glassy carbon disk electrode which after modification with poly(Alizarin Violet 3B), multiwalled carbon nanotubes and graphene enables simultaneous determination of the drugs acetaminophen (AP), theophylline (TP) and caffeine (CF). The electrochemical response to AP, TP and CF at the modified electrode was studied by cyclic voltammetry, and the results revealed an excellent electrocatalytic activity towards the oxidation of the three analytes at potentials of typically 0.5, 1.15 and 1.4 V (vs. SCE) respectively. The anodic peaks are well defined and occur at lower oxidation potential and enhanced oxidation peak currents (compared to an unmodified electrode). Simultaneous differential pulse voltammetric measurements resulted in calibration plot for AP, TP and CF were obtained that cover range from 0.2 to 100 μM for AP, from 0.5 to 120 μM for TP, and from 1.0 to 120 μM for CF. The respective detection limits are 0.01, 0.02 and 0.10 μM. The method was applied to simultaneous determination of AP, TP and CF in spiked human serum and gave satisfactory results.
Graphical Abstract
A nanocomposite consisting of poly(Alizarin violet), multiwalled carbon nanotubes and graphene was used to modify a glassy carbon electrode which then can be used simultaneously determine acetaminophen, theophylline and caffeine.
... It is most commonly consumed by humans in infusions extracted from the seed of the coffee plant and the leaves of the tea bush (Peters, 1967). Also caffeine is found in various kinds of foods and drinks that we consume in daily life (Singh and Sahu, 2006). In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness (Lovett, 2008). ...
This study was conducted to determine the effect of roasting conditions on chemical constituents of Vietnam robusta coffee. The contents of acrylamide, chlorogenic acid and tannins were higher in green coffee than in roasted coffee and decreased as roasting condition increased, which ranged from 6.53 to 91.36 μg/100g, 1.54 to 55.51 mg/g and 3.14 to 651.59 mg/10g, respectively. In addition, the content of trigonelline ranged from 1.43 to 64.24 mg/10g, which gave the highest value in green coffee, then decreased rapidly, while in the Italian roast it was not present at all. Caffeine content ranged from 15.30 to 35.91 mg/g and presented the lowest value in the case of green coffee, then increased reaching the highest value at 240 o C, after that decreasing gradually and slowly.
... And also this method has been applied in the analysis of paracetamol and caffeine in various synthetic materials. Singh and Sahu [25] have developed a method for the determination of caffeine based on the oxidation of caffeine with sodium metaperiodate in the presence of acetic acid. This is followed by coupling with 3-methyl-2-benzothiazoline hydrazone hydrochloride (MBTH) which results in a blue colored product with max at 630 nm. ...
The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine.
A newly synthesized xanthate functionalized chlorinated polypropylene (PP-Xa) was used as adsorbent for the orbital shaker based on dispersive solid phase microextraction (OS-DSPME) of caffein from several tea, coffee, energy drink, coca-cola and chocolate samples using UV-vis. spectrophotometer. Synthesized PP-Xa was characterized using Fourier Transform Infrared spectroscopy (FTIR-ATR) and nuclear magnetic resonance spectroscopy (¹H NMR). Various parameters like pH, PP-Xa amount, extraction time, type of eluent and its volume were optimized. Linear range, detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD), recovery values, and enrichment factor (EF) were found 90–1000 μg L⁻¹, 27.3 µg L⁻¹, 90 µg L⁻¹, 1.9–2.6%, 98 ± 2%, and 167, respectively. Adsorption capacity of PP-Xa was found 271.9 mg g⁻¹. Standard addition and reference method were used for confirm the accuracy of present method.
In this study, a square wave voltammetric method for determination of theophylline in tablet formulation based on EDTA salt modified carbon paste electrode is presented. CV, FT-IR, and EIS results confirmed modification of the carbon paste with EDTA salt. In contrast to the unmodified carbon paste electrode, the modified carbon paste electrode showed irreversible oxidation of theophylline with considerable current enhancement. Investigation of the effect of scan rate on the Ip and Ep response of the modified electrode for theophylline revealed predominantly diffusion controlled oxidation kinetics. Under the optimized conditions, square wave oxidative peak current of theophylline in pH 7.0 PBS showed linear dependence on concentration in the range 10-200 μM with determination coefficient (R2), limit of detection, and limit of quantification of 0.99782, 0.0257 μM, and 0.0857 μM, respectively. Detection of an amount of theophylline in the analyzed tablet formulation with 1.85% error from its nominal content (120 mg/tablet) confirmed the accuracy of the developed method. Spike and interference recovery results of 98.59%, and 95.7-100%, respectively validated the applicability of the developed method for determination of theophylline content in tablet samples.
Background: In recent times, development of an efficient electrode material for the determination of caffeine content in beverages and other related sources becomes essential. In this work, for the first time, a novel electrochemical sensor based on carbonized Cu-4,4’-bipyridine-trimesic interlinked metal-organic framework (CBT-MOF) was prepared, characterized by various surface analytical techniques and employed for the effective sensing of caffeine.
Method: Copper-4,4’-bipyridine-trimesic acid interlinked MOF (CBT-MOF) was prepared by simple solvo-thermal method and it was carbonized at different temperatures. Significant findings The superiority of CBT-500 may be associated with rise in the Conductivity of the copper oxide nanoparticles by increasing the carbonizing temperature at 500 °C. which enhances the electron transfer kinetics between the analyte and the copper oxide nanoparticle. Increase in temperature above 500 °C, (CBT-600 and CBT-700), results in lower conductivity, thereby decreasing the electron transfer kinetics between the electrode/electrolyte interface. As expected, the amperometric detection of caffeine on fabricated electrode material provided a linear dynamic range from 1 to 10 μM with a low detection limit and higher sensitivity of 0.0190 μM and 0.0848 mA μM⁻¹ cm⁻². Further, the fabricated electrode material remained stable, leading to a promising sensor material for the analysis of caffeine in coffee samples.
An electrochemical sensor based on glassy carbon electrode modified with reduced graphene oxide-sodium dodecyl sulfate-Nafion* composite film was constructed and used to determine theophylline. The synthesized graphene oxide and surface morphology of the reduced graphene oxide-sodium dodecyl sulfate-Nafion film were characterized using IR spectroscopy, X-ray diffraction studies, and electrochemical impedance spectroscopy. The electrochemical behavior of the theophylline on the modified electrode was investigated using cyclic voltammetry and adsorptive differential pulse voltammetry. Under optimized analytical conditions, the electrode showed a linear response at concentrations of theophylline of 0.01–0.10, 0.1–1.0, and 1.0–40 µmol L−1 with the detection limit of 5 nmol L−1.
In this research the methods of measuring major bioactive compounds in coffee beans,
their optical transition properties, self-association, hetero-association and thermodynamic
properties were investigated by experimental and computational methods. The implemented
methods for determination the contents of biocactive compounds in coffee beans
are the extraction of caffeine from water solution or liquid-liquid extraction and fitting
Gaussian function to the spectrum of the compound by non-linear curve fitting based on
the Lavenberg-Marquardt algorithm to eliminate the possible interferences. The contents
of caffeine and chlorogenic acids determined by these methods for green coffee beans
are in the ranges of 0.90-1.27 %, 6.05-6.25 % respectively. The optical transition properties
of caffeine, caffeic and 5-caffeoylquinic acids were determined in different solvents by
integrating the absorption coefficients in the wave number regions. The calculated values
of transition dipole moment of caffeine, caffeic and 5-caffeoylquinic acids in water in
their wave number regions are 10.40×10−30, 19×10−30, 20×10−30Cm respectively. The corresponding
oscillator strength are 0.19, 0.49 and 0.56. The concentration dependent selfassociation
of caffeic, 5-caffeoylquinic acids and their hetero-association were analyzed
by dimer model and Benesi-Hildebrand approaches. The thermodynamic parameters, enthalpy,
Gibbs free energy and entropy of dimerzation reactions were calculated from Van’t
Hoff equation. The calculated molar enthalpy change for caffeic and 5-caffeoylquinic acids
of self-association are -63.20, -12.89 kJmol−1 respectively.In addition, the time dependent
Schrodinger equations were solved by semi-classical approach to relate the theoretical expressions
with the experimentally measurable quantities.
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An electrochemical sensor based on tungsten trioxide nanoparticles and multiwall carbon nanotubes composite was developed for the determination of theophylline (THP). WO3 nanoparticles were synthesized by the precipitation reaction in acidic media. The constructed sensor was applied for the quantification of theophylline by adsorptive stripping voltammetry. In order to achieve the best electrochemical response, the effects of different parameters such as scan rate, electrolyte solution conditions, pH and accumulation conditions were investigated. Under optimal statuses, the calibration curve represented a concentration linear range of 2.5 × 10⁻⁸–2.6 × 10⁻⁶ M and a low limit of detection 8.3 × 10⁻⁹ M. The sensor represented great selectivity for THP toward a wide diversity of foreign organic and inorganic chemicals. The modified sensor was used successfully for the measurement of theophylline in pharmaceutical and biological media.
The chemiluminescence (CL) behaviour of the luminol–potassium periodate system enhanced by CdTe quantum dots capped with thioglycolic acid (TGA–CdTe QDs) was studied using kinetic experiments, CL spectra, UV–vis absorption spectra and fluorescence spectra. The production of oxygen‐containing reactant intermediates (O2•− and OH•) in the present CL system was verified by CL. The possible CL mechanism was discussed in detail. Furthermore, theophylline (THP) was determined based on its enhancement of the CL intensity of the CdTe QDs–luminol–potassium periodate system coupled with a flow‐injection technique. Under these optimized conditions, the linear range was found to be from 1.0 × 10−8 to 1.0 × 10−5 g/mL with a detection limit of 2.8 × 10−9 g/mL (3σ). The recoveries for the determination of THP in tablets were from 98.2 to 99.6%.
This article suggests a new sequential injection analysis chemiluminescence (SIA‐CL) strategy for monitoring the caffeine (CAF) content in soft and energy drinks using the catalytic activities of different nano‐metal oxides. The present study describes three different SIA‐CL systems (luminol–ferricyanide (III) coupled with Fe2O3 or ZnO nanoparticles (NPs), and luminol–H2O2 coupled with CuONPs. All experimental conditions were optimized and the linear concentration ranges of pure CAF were evaluated using the calibration graphs. The selectivity of the developed SIA‐CL systems was studied under the influence of various interfering species that may be present in soft or energy drinks such as sodium ions, sucrose, glucose, sodium benzoate, sodium citrate, riboflavin, niacin, citric, phosphoric and ascorbic acids. International Council for Harmonization (ICH) guidelines were obeyed for the validation of the suggested CL methods. The developed SIA‐CL systems displayed linear relationships over the concentration ranges 1.0–350, 5.0–400 and 10.0–400 μg ml⁻¹ with Fe2O3 NPs, ZnO NPs and CuO NPs, respectively. The recorded lower limits of detection and quantification were 0.7, 2.7 and 7.8 μg ml⁻¹, and 1.0, 5.0 and 10.0 μg ml⁻¹ for the previously mentioned SIA‐CL systems. The results revealed high selectivity for CAF determination and were in good agreement with those obtained by other reported methods.
P>Background: The electrochemical sensing of drugs in pharmaceutical formulations and biological matrices using molecular-imprinting polymer (MIP) as a recognition element combined with different electrochemical signal transduction has been widely developed. The MIP electrochemical sensors based on nanomaterials such as graphene, carbon nanotubes, nanoparticles, as well as other electrode modifiers incorporated into the MIPs to enhance the performance of the sensor, have been discussed. The recent advances in enantioselective sensing using MIP-based electrochemical sensors have been described.
Methods: The molecular imprinting has more than six decades of history. MIPs were introduced in electrochemistry only in the 1990s by Mosbach and coworkers. This review covers recent literature published a few years ago. The future outlook for sensing, miniaturization and development of portable devices for multi-analyte detection of the target analytes was also given.
Results: The growing pharmaceutical interest in molecularly imprinted polymers is probably a direct consequence of its major advantages over other analytical techniques, namely, increased selectivity and sensitivity of the method. Due to the complexity of biological samples and the trace levels of drugs in biological samples, molecularly imprinted polymers have been used to improve the response signal, increase the sensitivity, and decrease the detection limit of the sensors. The emergence of nanomaterials opened a new horizon in designing integrated electrochemical systems. The success of obtaining a high-performance electrochemical sensor based on MIPs lies in the kind of material that builds up the detection platform.
Conclusion: The novel approaches to produce MIP materials, combined with electrochemical transduction to develop sensors for screening different pharmaceutically active compounds have been overviewed. MIPs may appear indispensable for sensing in harsh conditions, or sensing that requires longterm stability unachievable by biological receptors. The electrochemical sensors provide several benefits including low costs, shortening analysis time, simple design; portability; miniaturization, easy-touse, can be tailored using a simple procedure for particular applications. The performance of sensor can be improved by incorporating some conductive nanomaterials as AuNPs, CNTs, graphene, nanowires and magnetic nanoparticles in the polymeric matrix of MIP-based sensors. The application of new electrochemical sensing scaffolds based on novel multifunctional-MIPs is expected to be widely developed and used in the future.</P
Hybrid-monomers double templates molecularly imprinted polymers (HDMIPs) were prepared by two methods with in-situ polymerization technique. Hybrid-monomers were prepared with 3-aminopropyltriethoxysilanes (APTES) as an inorganic source and methacrylic acid (MAA)/acrylamide (AM) as an organic source. HDMIPs were used as sorbents for selective isolation and determination theophylline and quercetin in green tea extracts. Fourier transform infrared and field emission scanning electron microscope were used to characterize the morphology and structure information of HDMIPs. The recognition ability and binding capability of HDMIPs for analytes were evaluated by static absorption and Scatchard analysis. The adsorption equilibrium data of two analytes were investigated using three different analysis models: linear, Langmuir and Freundlich. With optimization of solid-phase extraction procedure, a reliable analytical method was developed for highly recognition towards theophylline and quercetin in green tea with satisfactory extraction recoveries of 96.68% and 88.92%. The recoveries of proposed method at three spiked levels analysis were 84.62-96.68% for theophylline and 82.88-88.92% for quercetin. The HDMIPs showed good performance for two targets, and the proposed approach with high affinity of hybrid molecularly imprinted polymers might offer a novel method for the purification of complex samples.
Coffee is the most popular beverage all over the world. Bioactive profile of coffee is enriched with important phytochemicals dominated by the caffeine and chlorogenic acid. Present project uploading the chemical profile of different coffee samples and evaluating the effect of decaffeination on their chemical status. Caffeine contents were varied between 0.036 to 1.18%. Result regarding proximate constitutes increased as a function of storage .Moisture content varies between 1.458 to 1.558% and highest found at 45th day of storage. Among the mineral constituent K dominated as 1386.66 and least was detected in Zn as 0.10mg/100g. Total acidity and PH also changed with change of storage interval. Total acidity was highest in T2 as 120.417 and decreased with increased of storage interval. Total polyphenols found to be in the range of 1490 to 1790 mg /100g and it was least in decaffeinated samples. A same trend was observed for chlorogenic acid that was ranges from 1124 to 1542 mgg/100g and it was also showed reduce value after decaffination. chiorcy was detected negative for all the samples. Different Sensory attributes like taste, flavour, aroma, and over all acceptability pronounced the T4 as best treatment and least scored by the T1.
In this work, a novel poly(folic acid)/ graphene composite film modified electrode was developed to construct an electrochemical sensor for simultaneous determination of theophylline (TP) and caffeine (CAF). The fabrication and characterization of nanocomposite film were investigated in details by electrochemistry and scanning electron microscopy. This new electrochemical sensor displayed superior electrocatalytic property to the oxidation of TP and CAF, which obviously improved the sensitive detection of the two compounds in the terms of high sensitivity and wide linear range. Under the optimized experimental conditions, the detection limits were obtained to be 0.03 μ mol L⁻¹ for TP and 0.08 μmol L⁻¹ for CAF, respectively. The novel sensor was successfully used for the simultaneous detection of TP and CAF in food samples.
Resolution of binary mixtures of theophylline (THEO), montelukast (MKST) and loratadine (LORA) with minimum sample pre-treatment and without analyte separation has been successfully achieved by multivariate spectrophotometric calibration, together with partial least-squares (PLS-1), principal component regression (PCR) and hybrid linear analysis (HLA). Data of analysis were obtained from UV–Vis spectra of three compounds. The method of central composite design was used in the ranges of 2–14 and 3–11 mg L–1 for calibration and validation sets, respectively. The models refinement procedure and their validation were performed by cross-validation. The minimum root mean square error of prediction (RMSEP) was 0.173 mg L⁻¹ for THEO with PCR, 0.187 mg L–1 for MKST with PLS1 and 0.251 mg L–1 for LORA with HLA techniques. The limit of detection was obtained 0.03, 0.05 and 0.05 mg L⁻¹ by PCR model for THEO, MKST and LORA, respectively. The procedure was successfully applied for simultaneous determination of the above compounds in pharmaceutical tablets and human plasma. Notwithstanding the spectral overlapping among three drugs, as well as the intrinsic variability of the latter in unknown samples, the recoveries are excellent.
The densities (rho), viscosities (eta), and H-1 nuclear magnetic resonance (NMR) studies for caffeine, theophylline, and theobromine in water and in aqueous solutions of 0.10, 0.25, 0.50, 0.75, and 1.00 mol.kg(-1) sodium chloride over a temperature range T = 288.15-318.15 K and at p = 101.325 kPa have been carried out using vibrating-tube digital densimeter, micro-Ubbelohde type capillary viscometer, and Broker (AVANCE-III, HD 500 MHz) NMR spectrometer, respectively. From the density and viscosity data, apparent molar volume (V-2,V-phi), partial molar volume at infinite dilution (V-2,phi(0)), viscosity B-coefficient, corresponding transfer (Delta V-tr(2,phi)0 and Delta B-tr) and other related parameters have been calculated. The trends in transfer parameters reveal the dominance of hydrophilic ionic interactions at lower molalities of NaCl while hydrophobic ionic interactions at higher molalities of NaCl. The expansibilities and dB/dT data show the structure breaking behavior of theophylline and theobromine in water and in aqueous solutions of NaCl. However, behavior of caffeine is exceptional. The increase in chemical shift (delta) values with increasing molalities of NaCl also signifies the predominance of solute-cosolute interactions over the dehydration process. The results have further been discussed and rationalized in terms of various interactions.
Methylxanthines are a group of phytochemicals derived from the purine base xanthine and obtained from plant secondary metabolism. They are unobtrusively included in daily diet in common products as coffee, tea, energetic drinks, or chocolate. Caffeine is by far the most studied methylxanthine either in animal or epidemiologic studies. Theophylline and theobromine are other relevant methylxanthines also commonly available in the aforementioned sources. There are many disseminated myths about methylxanthines but there is increased scientific knowledge to discuss all the controversy and promise shown by these intriguing phytochemicals. In fact, many beneficial physiologic outcomes have been suggested for methylxanthines in areas as important and diverse as neurodegenerative and respiratory diseases, diabetes or cancer. However, there have always been toxicity concerns with methylxanthine (over)consumption and pharmacologic applications. Herein, we explore the structure-bioactivity relationships to bring light those enumerated effects. The potential shown by methylxanthines in such a wide range of conditions should substantiate many other scientific endeavors that may highlight their adequacy as adjuvant therapy agents and may contribute to the advent of functional foods. Newly designed targeted molecules based on methylxanthine structure may originate more specific and effective outcomes.
Coffee, Tea and soft drinks are very commonly used beverages in all over the world. The caffeine is the main stimulant occurred in all drinks. Caffeine stimulates the central nervous system, relaxation, myocardial stimulation, recreation etc. It can provide energy, decrease fatigue, enhance performance etc. Caffeine having medicinal properties so can be used along with other drugs for headache, stimulation, muscle relaxant etc. Up to certain limit caffeine is useful but overdose of caffeine starts side effects on the human body. There are various instrumental methods can be used for the determination of caffeine in plants, coffee, tea, soft drinks and pharmaceutical formulation in presence of other drugs. HPLC methods are the most common, reliable methods for the determination caffeine in complex sample. Very low concentration of caffeine can be determined with high accuracy and precision. Here in this review we have summarized various HPLC methods used for the caffeine analysis in various samples and complex mixtures with their chromatographic column, mobile phase, flow rate, detector etc.
A high performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of theophylline and its metabolites, with caffeine and its metabolites. The method is simple and applicable to planning the administration of theophylline. We used a column-switching system in combination with atmospheric pressure chemical ionization liquid chromatography-mass spectrometry (LC-APCI-MS) for the determination of theophylline and its metabolites in biological samples. In the mass spectrum, the molecular ions of these drugs and metabolites were clearly observed as base peaks. The method is sufficiently sensitive and accurate for the pharmacokinetic studies of these drugs.
An accurate, simple, reproducible and sensitive method for the determination of paracetamol, caffeine and dipyrone was developed and validated. Paracetamol, caffeine and dipyrone were separated using a μ-Bondapack C8 column by isocratic elution with a flow rate of 1.0 ml/min. The mobile phase composition was 0.01 M KH2PO4_-methanol-acetonitrile-isopropyl alcohol (420: 20: 30: 30) (v/v/v/v) and spectrophotometric detection was carried out at 215 nm. The linear range of determination for paracetamol, caffeine and dipyrone were 0.409-400 μg/ml. 0.151-200 μg/ml and 0.233-600 μg/ml, respectively. The method was shown to be linear, reproducible, specific, sensitive and rugged.
The luminescence properties of solutions of caffeine and theophylline in methanol are observed. The effects of the solvent pH, the presence of a heavy atom and the matrix or substrate on the fluorescence and phosphorescence properties of the compounds are evaluated. Caffeine and theophylline fluorescence can be observed at room temperature from dilute methanolic solutions and strong phosphorescence is observed at low temperature when the matrix is in a polycrystalline state. Acidic and basic media cause spectral changes and reduce the intensity of the low temperature phosphorescence. Iodide is a good heavy-atom enhancer of both the low temperature and room temperature phosphorescence of caffeine and theophylline. The intensity of the phosphorescence at room temperature and when spotted on filter paper depends on the type of filter paper and the pH of the spotting solution and/or the pH of the wet surface at the moment of spotting. Theophylline is more sensitive than caffeine to the microenvironment. Under the appropriate experimental conditions, both low temperature and room temperature phosphorescence could be used as analytical tools for the determination of caffeine and theophylline.
The aim of the present study was to develop a capillary gas chromatography method for the quantitative analysis of caffeine in Brazilian guarana as seed powder, dried crude ethanol extracts, and lyophilized water extracts with the addition of 7β-Hydroxyethyltheophylline as the internal standard. The experimental protocol, the conditions, the analytical instrumentation, the recovery studies, as well as the analysis of seven different commercial batches of guarana, are presented and discussed.
Accurate, sensitive and precise derivative ultraviolet Spectrophotometric and high-performance liquid chromatographic (HPLC) methods are described for the simultaneous determination of three natural methyl xanthines (theobromine, theophylline and caffeine) in various food products. The derivative UV-spectro-photometry, with zero crrosing technique of measurement was selected for determination of theobromine and theophylline. First-derivative procedure (D1) was adopted for theobromine determination in the presence of theophylline and caffeine; and second-derivative procedure (D2) was adopted for theophylline determination in the presence of theobromine and caffeine. Caffeine was determined by compensation method using the zero order spectrophotometry. The second method was based on HPLC on a reversed phase column, using a mobile phase of 0.01 M sodium acetate solution: acetonitrile (85:15%) at PH 4.0 with detection at 272 nm. Both methods show good linearity, precision and reproducibility. The developed methods proved to be applicable for the determination of methyl xanthines in various food products.The validity of the proposed methods were tested by analyzing laboratory-prepared mixtures containing the three components in various proportions and by analyzing several food products spiked with a known concentration of the three components.
A single triparameter flow-through sensor with U.V. detection is described in this study for the simultaneous determination of acetaminophen, acetylsalicylic acid and caffeine. The use of an solid phase (C18 silica gel) placed in an on-line microcolumn provides the sequential arrival of the analytes to the detection solid zone (also C18 silica gel beads placed in a flow cell), making possible the determination with only one injection. A flow rate of 1.42 mL min was pumped and detection wavelength was 272 nm. The linear dynamic ranges were 10–100, 40–500 and 4–50 µg mL, for acetaminophen, acetylsalicylic acid and caffeine, respectively. Limit of detection were from 0.3 to 0.8 µg mL and limit of quantitation were from 1.0 and 2.7 µg mL with RSDs from 1.2 to 3.4 (n = 10), respectively. The proposed method was applied to the determination of acetaminophen, acetylsalicylic acid and caffeine in pharmaceutical preparations. The results were compared with those obtained from an HPLC method and they showed a good agreement.
In acid solution, caffeine, theobromine, and theophylline are rapidly and quantitatively oxidized with electrogenerated chlorine in a stoichiometric ratio of 2 : 5 to give alloxan and urea. Procedures for the coulometric determination of microgram amounts of caffeine, theophylline, and theobromine in model solutions, caffeine in tea and coffee samples, and caffeine and theophylline in some pharmaceutical preparations were developed.
Two new spot-tests for purines are described together with a new sensitive determination of caffeine. The spot tests involve a fluorometric reaction with 4,5-dimethyl-o-phenylenediamine after oxidation with N-bromosuccinimide. Caffeine treated in this manner exhibits a blue fluorescence with excitation maxima at 340 and 390 nm, and an emission maximum at 480 nm. The fluorometric reaction may be used to determine caffeine in the range 0.01–10, μg/ml with a relative standard deviation of 0.9% for 0.1 μg/ml caffeine. The method has been used to determine caffeine in cough syrups.
Some monomethylxanthine and methyluric acid derivatives of theophylline and caffeine have been studied to explore whether they possess pharmacological and biochemical activities similar to those of their parent compounds. Both 3-methylxanthine and 1-methylxanthine, but not 1,3-dimethyluric acid or 3-methyluric acid, produced the same maximal relaxation of guinea pig tracheal muscle as did theophylline. The EC50 values for theophylline and 3-methylxanthine were not significantly different, whereas those for 1-methylxanthine, 1,3-dimethyluric acid and 3-methyluric acid were significantly higher than that if theophylline. In the Langendorff guinea pig heart, theophylline and 3-methylxanthine caused essentially identical increases in cardiac contractile force. Although less effective than theophylline, 1-methylxanthine and caffeine produced equivalent increases in cardiac contractility. At concentrations higher than those effective for the methylxanthines, 1,3-dimethyluric acid markedly increased contractile force. 3-Methylxanthine inhibited cyclic AMP phosphodiesterase to a lesser extent than did theophylline at both 1.4 and 400 μM cyclic nucleotide concentrations. However, at the higher substrate concentration, cyclic GMP phosphodiesterase activity was inhibited by 3-methylxanthine more than by theophylline. Thus, it appears that the monomethylxanthine and methyluric acid derivatives of theophylline and caffeine possess a spectrum of pharmacological activity similar to that of their parent compounds, a finding which raises important questions about various aspects of the current therapeutic use of methylxanthines.
The seeds of Guaraná are rich in xanthines and are used for the preparation of guaraná powder which is very commonly given to horses as a 'tonic' in Brazil. In this paper, the xanthine content of guaraná powder was determined, in addition to its clearance time in horses. Thin-layer chromatography was used as a screening procedure and high-performance liquid chromatography was performed to quantify the drugs in both the powder and urine samples. The guaraná powder was found to contain 2.16, 1.10 and 36.78 mg g-1 of theobromine (TB), theophylline (TP) and caffeine (CF), respectively, and in urine it was possible to detect TB and TP up to 13 d and CF up to 9 d after the administration of guaraná powder.
An ODS column dynamically coated with zwitterionic bile acid derivative, 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS), was evaluated for direct injection determination of drugs in blood serum by HPLC. Polar functional groups such as sulfonate, ammonium and the three hydroxyl groups in CHAPS protruding towards an aqueous mobile phase formed a hydrophilic layer over the ODS reversed-phase surface, which resulted in high molecular mass compounds such as proteins being prevented from penetrating into the internal hydrophobic region. The bulk of the proteins were eluted as an unretained or nearly unretained band by using 0.2 mM sodium hydrogenphosphate solution (pH 7.4) as the mobile phase. In contrast, small molecules such as some inorganic anions and aromatic compounds were retained and thereby separated from one another. It was confirmed that the ODS column modified with CHAPS acts as a restricted access-type column with a hydrophobic interior and a hydrophilic exterior. Hence biological fluids could be directly injected into the CHAPS-coated ODS column. The present HPLC system using the CHAPS-coated ODS column was applied to the determination of theophylline and caffeine in human blood serum. The detection limits for the two drugs with UV absorption at 273 nm were 0.2 and 0.5 mg l-1 (injection volume 20 microliters) and the relative standard deviations of peak area measurements were < 1.4% and 2.2%, respectively, for 10 replicate measurements of serum spiked with 5 mg l-1 of each of the drugs.
A capillary electrochromatography (CEC) method has been developed for the separation of theophylline, caffeine and five related drugs on a normal-phase column with UV or photodiode array detection. Several binary, ternary and quaternary mobile phase compositions are evaluated for optimal resolution and elution of these drug analytes. The importance of selecting suitable organic solvents, buffer electrolyte, pH and applied voltage is demonstrated by a systematic study. Excellent separation is achieved for the eight drugs using a ternary mobile phase composition of isopropanol/hexane/1 mM Tris (52:40:8, pH 8), with an efficiency of 63000 theoretical plates per meter at room temperature. Detection limits are typically at the low microg/mL level. The developed method is simple to use and it gives acceptable day-to-day reproducibility.
An accurate, simple, reproducible and sensitive method for the determination of paracetamol, caffeine and codeine phosphate has been developed and validated. Paracetamol, caffeine and codeine phosphate were separated using a muBondapack C8 column by isocratic elution with flow rate 1.0 ml/min. The mobile phase composition was 420/20/30/30 (v/v/v/v) 0.01 M KH2PO4, methanol, acetonitrile, isopropyl alcohol and spectrophotometric detection was carried out at 215 nm. The linear range of detection for paracetamol, caffeine and codeine phosphate were between 0.400 and 1500 microg/ml; 0.075 and 90 microg/ml; 0.300 and 30 microg/ml, respectively. The method has been shown to be linear, reproducible, specific, sensitive and rugged.
A novel ion chromatographic method was proposed for the simultaneous determination of artificial sweeteners (sodium saccharin, aspartame, acesulfame-K), preservatives (benzoic acid, sorbic acid), caffeine, theobromine and theophylline. The separation was performed on an anion-exchange analytical column operated at 40 degrees C within 45 min by an isocratic elution with 5 mM aqueous NaH2PO4 (pH 8.20) solution containing 4% (v/v) acetonitrile as eluent, and the determination by wavelength-switching ultraviolet absorbance detection. The detection limits (signal-to-noise ratio 3:1) for all analytes were below the sub-microg/ml level. Under the experimental conditions, several organic acids, including citric acid, malic acid, tartaric acid and ascorbic acid, did not interfere with the determination. The method has been successfully applied to the analysis of various food and pharmaceutical preparations, and the average recoveries for real samples ranged from 85 to 104%. The levels of all analytes determined by this method were in good agreement with those obtained by the high-performance liquid chromatographic procedure. The results also indicated that ion chromatography would be possibly a beneficial alternative to conventional high-performance liquid chromatography for the separation and determination of these compounds.
Classical least-squares (CLS) and principal component regression (PCR) techniques were proposed for the simultaneous analysis of tablets containing acetaminophen and caffeine without using a chemical separation procedure. The chemometric calibrations were prepared by measuring the absorbances values at the 15 wavelengths in the spectral region 215-285 nm and by using a training set of the mixtures of both drugs in 0.1 M HCI. The obtained chemometric calibrations were used for the estimation of acetaminophen and caffeine in samples. The numerical calculations were performed with the 'MAPLE V' software. By applying two techniques to synthetic mixtures, the mean recoveries and the relative standard deviations in the CLS and PCR techniques were found as 99.5 and 1.29, 99.7 and 1.00% for acetaminophen and 99.9 and 1.92, 100.0 and 1.178% for caffeine, respectively. Our results were compared with those obtained previously by one of us considering HPLC method as a reference method. These two methods were successfully applied to a pharmaceutical tablet formulation of two drugs.
A kinetic-spectrophotometric method for the determination of theophylline, dyphylline and proxyphylline, based on their azo coupling reaction with the diazonium ion of sulfanilic acid after a treatment with alkali, is proposed. The absorbance is recorded from 340 to 600 nm every second during reaction for 90 s, and calibration is performed by partial least-squares regression, using first derivative spectra values. Mixtures containing 2.5-13 micro g mL(-1) dyphylline and proxyphylline, and 2-9 micro g mL(-1) theophylline were successfully resolved with root mean squared errors of prediction (RMSEP) of 0.4, 0.3, and 0.2 for dyphylline, proxyphylline, and theophylline, respectively. The proposed method was satisfactorily applied to the determination of the three compounds in a commercially available pharmaceutical preparation and provided results similar to those obtained by HPLC.
Methyl xanthines: Toxicity to human—2. Caffeine
- Stavriv
B. Stavriv, Methyl xanthines: Toxicity to human—2. CaVeine, Food Chem. Toxicol. 26 (1998) 645–662.
Direct determina-tion of caVeine and theophylline by gas chromatography
- X Qing-Qin
- D L Ming
- J.-P Wang
- A H Bai
X. Qing-qin, D.L. Ming, J.-P. Wang, A.H. Bai, Direct determina-tion of caVeine and theophylline by gas chromatography, Fenxi Kexue Xuebao 18 (2002) 520–525.
Simultaneous determination of the components in theophylline tablets by statis-tical simulation spectrometry
- L Huan
- K Qiming
- X Wang
- L Xu
- B Kaishun
L. Huan, K. Qiming, X. Wang, L. Xu, B. Kaishun, Simultaneous determination of the components in theophylline tablets by statis-tical simulation spectrometry, Huaxue Fenxi Jiliang 11 (2002) 11–14.
Spectrophotometric determi-nation of three components in aspirin compound tablets by multi-plier function method
- L Wen
- M D Zhu
- L Jiu
- K J Deng
L. Wen, M.D. Zhu, L. Jiu, K.J. Deng, Spectrophotometric determi-nation of three components in aspirin compound tablets by multi-plier function method, Guangpu Shiyanshi 18 (2001) 197–200.
Simultaneous determination of caVeine, theophylline, and theobromine by HPLC
- M L Qi
- P Wang
- Y X Lang
- J L Lang
- R N Fu
M.L. Qi, P. Wang, Y.X. Lang, J.L. Lang, R.N. Fu, Simultaneous determination of caVeine, theophylline, and theobromine by HPLC, J. Chromatogr. Sci. 40 (2002) 45–48.
Determination of xanthines by HPLC and TLC horse urine after ingestion of guarana powder
- Salvadori
M.C. Salvadori, E.M. Reiser, L.M. Ribeironeta, Determination of xanthines by HPLC and TLC horse urine after ingestion of gua-rana powder, Analyst 119 (1994) 2701–2703.
Her Majesty’s Stationery Office
- British Pharmacopoeia
Simultaneous determination of caffeine, theophylline, and theobromine by HPLC
- Qi
Kinetic spectrophotometric determination of theophylline, dyphylline, and proxyphylline by use of partial least square regression
- Turriaga
Simultaneous determination of the components in theophylline tablets by statistical simulation spectrometry
- Huan
Simultaneous determination of artificial sweetners, preservatives, caffeine, theobromine, and theophylline in food and pharmaceutical preparations by ion chromatography
- Qing-Chun
Spectrophotometric determination of three components in aspirin compound tablets by multiplier function method
- Wen
Direct determination of caffeine and theophylline by gas chromatography
- Qing-qin