Figure - available via license: CC BY-NC-ND
Content may be subject to copyright.
Source publication
A sensitive procedure was developed for the simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (TRP) using a composite electrode based on carbon black nanoballs (CBNB) and carbon nanotubes (CNTs). The CBNB/CNTs/GCE presented well-defined voltammetric peaks for AA, DA, UA and TRP. The proposed procedure ha...
Similar publications
In this paper, a kind of conical cup-stacked carbon nanotubes (CSCNTs) grown by the microwave irradiation of the mixture of ferrocene and carbon black nanoparticles is reported. They are characterized by the long-cone shape, the nearly unchanged wall thickness and the huge hollow core. SEM and TEM analyses reveal that they are formed by the stackin...
Citations
... Trp was also determined simultaneously with uric acid [129,130], dopamine [131,132], ascorbic acid [133,134], acetaminophen [135][136][137], epinephrine [138], Tyr [139][140][141][142][143] and melatonin [144] with nanomaterial-based sensors. For example, Zhu et al. synthesized nanocomposite composed of ferroferric oxide nanoparticles (Fe 3 O 4 ) functionalized polyoxometalates (H 6 PMo 9 V 3 O 40 ⋅nH 2 O) by using one-step hydrothermal doped method to fabricate modified carbon paste electrode for simultaneous detection of β-nicotinamide adenine dinucleotide and L-Trp in human serum, with LODs of 53 nM and 17 nM, respectively. ...
Amino acids are the building blocks of proteins and muscle tissue. They also play a significant role in physiological processes related to energy, recovery, mood, muscle and brain function, fat burning and stimulating growth hormone or insulin secretion. Accurate determination of amino acids in biological fluids is necessary because any changes in their normal ranges in the body warn diseases like kidney disease, liver disease, type 2 diabetes and cancer. To date, many methods such as liquid chromatography, fluorescence mass spectrometry, etc. have been used for the determination of amino acids. Compared with the above techniques, electrochemical systems using modified electrodes offer a rapid, accurate, cheap, real-time analytical path through simple operations with high selectivity and sensitivity. Nanomaterials have found many interests to create smart electrochemical sensors in different application fields e.g. biomedical, environmental, and food analysis because of their exceptional properties. This review summarizes recent advances in the development of nanomaterial-based electrochemical sensors in 2017-2022 for the detection of amino acids in various matrices such as serum, urine, blood and pharmaceuticals.
... However, during the food intake these values are 75 -125 mg /day (AA) and 900 -1000 mg/day (Tr) [12], [13]. A major issue for simultaneous sensing of AA and Tr is that they undergo the same potential using conventional glassy carbon or gold electrode with a distinct fouling outcome, which results in poor reproducibility [14]- [18]. Till now, several analytical methods, like capillary electrophoresis, highperformance liquid chromatography, and fluorescence, have been reported to address this issue [19], [20]. ...
Herein, a novel, flexible and inexpensive carbon-cloth based electrochemical device (CCED) is proposed with polyimide (PI) sheet as a base substrate. CC, embedded with numerous microfibers, was used as a sensing substrate. A CO
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>
laser was employed for laser cutting three CC electrodes with desired dimensions, which were bonded on the PI sheet using a double-sided tape. Unmodified CC was used as working and counter electrodes, whereas Ag/AgCl ink modified CC was a reference electrode. For creating a hydrophobic region and insulating the electrodes, lamination process was used. Further ascorbic acid (AA) and tryptophan (Tr) were used as analytes for sensing with natural and unmodified CCED surface. The electrochemical response was analyzed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions, the CCED was observed to be capable of determining AA and Tr in a neutral pH (phosphate buffer solution) at 0.4 V and 0.6 V in a linear range of 30 -
$8000 ~\mu \text{M}$
and 20 –
$6000 ~\mu \text{M}$
, with LOD of
$21.76 ~\mu \text{M}$
, and
$11.84 ~\mu \text{M}$
respectively at (S/N=3). Additionally, it was thoroughly investigated for common interfering species including Xanthine (Xn), Hypoxanthine (Hx), Uric acid (UA), Cysteine (Cy), Glucose (G) and Folic Acid (FA). The sensing platform was successfully applied for determination of AA and Tr in human real serum sample with appreciable recoveries.
... To further study the reaction mechanism of AA, DA, and UA on the surface of CQDs-rGO/GCE electrochemical sensor, the effect of scan rate on the individual detection of 800 μM AA, 100 μM DA, and 500 μM UA were examined by CV method. As Fig. 4 shows, the oxidation peak current (I pa ) and reduction peak current (I pc ) of AA, DA, and UA increased linearly with increasing scan rates (from 50 to 250 mV s −1 ), and the linear equations were demonstrated as follows: It can be inferred from the results that the oxidation and reduction of AA, DA, and UA on CQDs-rGO/GCE were adsorption controlled processes [36,37]. The parameter settings of CV experiment were as follows: vertex 1 potential: − 0.6 V; vertex 2 potential: + 0.6 V; scanning speed: 50-250 mV s −1 ; scanning cycle: 3 weeks. ...
In this manuscript, carbon quantum dots-reduced graphene oxide (CQDs-rGO) nanocomposite was modified on the surface of glass carbon electrode (GCE) via an one-step co-deposition method to fabricate an effective electrochemical senor for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Due to the strong synergetic effect between CQDs and rGO, the sensor exhibited good selectivity and high catalytic activity toward AA, DA, and UA. The peak potential differences of simultaneous detection for AA-DA, DA-UA, and AA-UA were calculated as 0.147 V, 0.135 V, and 0.282 V, respectively. And the linear responses of AA, DA, and UA were found in the ranges of 0.2–0.9 mM (R2 = 0.99) and 1.4–4.2 mM (R2 = 0.99), 5–9 μM (R2 = 0.98) and 11–81 μM (R2 = 0.99), and 20–90 μM (R2 = 0.99) and 140–300 μM (R2 = 0.99), respectively. The as-prepared sensor contributed a fresh idea to the simultaneous detection of AA, DA, and UA, and has a broad prospect in practical application.
... Neurological disorders such as epilepsy are considered to be triggered due to lowering of DoP concentration as it regulates various vital neuronal functions within the brain and body. Specificity of the interaction (electron transfer, inner filter effect, π-π stacking) between the electrode and analytes makes it capable for simultaneous specific determination of biomolecules like DoP, uric acid, ascorbic acid, tryptophan for quantitative and or qualitative analysis [93]. Reproducibility, robustness, and specificity exhibited by such techniques are very important for the long and real-time analysis of neurotransmitters. ...
Epilepsy is a serious neurological disorder which affects every aspect of patients' life, including added socioeconomic burden. Unfortunately, only a few suppressive medicines are available, and a complete cure for the disease has not been found yet. Excluding the effectiveness of available therapies, the timely detection and monitoring of epilepsy are of utmost priority for early remediation and prevention. Inability to detect underlying epileptic signatures at early stage causes serious damage to the central nervous system (CNS) and irreversible detrimental variations in the organ system. Therefore, development of a multi-task solving novel smart biosensing systems is urgently required. The present review highlights advancements in state-of-art biosensing technology investigated for epilepsy diseases diagnostics and progression monitoring or both together. State of art epilepsy biosensors are composed of nano-enabled smart sensing platform integrated with micro/electronics and display. These diagnostics systems provide bio-information needed to understand disease progression and therapy optimization timely. The associated challenges related to the development of an efficient epilepsy biosensor and vision considering future prospects are also discussed in this report. This review will serve as a guide platform to scholars for understanding and planning of future research aiming to develop a smart bio-sensing system to detect and monitor epilepsy for point-of-care (PoC) applications.
A carbon nanotubes modified silver electrode (CNTs-Ag) was prepared via catalytic chemical vapor deposition and characterized. The morphology, crystallinity, elemental composition, and other quality parameters of the prepared electrode were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman techniques. The characterization results revealed the modification of the silver metal surface with CNTs of good characteristics. A sequential injection analysis (SIA) system was developed for studying the reaction of ascorbic acid with KIO3 using the prepared CNTs-Ag electrode. Electrodes were polarized with both direct current (DC) and periodic square wave (SW). Various experimental conditions affecting the differential electrolytic potentiometric (DEP) peak such as current density, SW bias value, and flow rate were appraised. Under the optimum conditions, good linear responses for ascorbic acid were obtained in the range of 60.0–850.0 µM for both types of polarization with detection limits of 14.0–19.0 µM. The results obtained showed that the periodic polarization method was more sensitive than DC polarization and the electrode response was faster. Ascorbic acid in pharmaceutical tablets was determined with satisfactory results using this method. The prepared CNTs-based electrode exhibited good performance for a long period of use. The method is simple, rapid, and inexpensive for routine analysis.
Total antioxidant capacity (TAC) can be evaluated by detecting the content of antioxidants, such as ascorbic acid, based on the enzyme-mimetic activity of nanomaterials. Herein, we fabricated a 3D-V2O5/NC nanocomposite using a self-templating strategy, which achieved ultrafine particles (∼2.5 nm), a porous carbon layer, large specific surface area (152.4 m2/g), N-doping and heterogeneous structure. The strong catalytic activity of 3D-V2O5/NC resulted from the integrated effect between the ultrafine structure of V2O5 nanoparticles and the 3D porous nitrogen-doped carbon framework, effectively increasing the number of active sites. This nanozyme presented a higher catalytic activity than its components or precursors in the nanocomposite (e.g., VN/NC, NC, V2O5, and VO2/g-C3N4). ROS scavenging experiments confirmed that the dual enzyme-like activity of 3D-V2O5/NC (catalase-like and oxidase-like) resulted from their co-participation of ‧O2-, h+ and ‧OH, among which ‧O2- played a crucial role in the catalytic color reaction. By virtue of the 3D-V2O5/NC nanoenzyme activity and TMB as a chromogenic substrate, the mixed system of 3D-V2O5/NC + TMB + H2O2 provided a low detection limit (0.03 μM) and suitable recovery (93.0-109.5%) for AA. Additionally, a smartphone-based colorimetric application was developed employing "Thing Identify" software to evaluate TAC in beverages. The colorimetric sensor and smartphone-detection platform provide a better or comparable analytical performance for TAC assessment in comparison to commercial ABTS test kits. The newly developed smartphone-based colorimetric platform presents several prominent advantageous, such as low cost, simple/rapid operation, and feasibility for outdoor use.
The present work reports a sensitive and simple sensor based on an electrochemically treated pencil graphite electrode (pre‐PGE) modified with multi‐walled carbon nanotubes (MWCNTs) for electrochemical determination of L‐tryptophan (L‐Try) detection in the presence of uric acid. Electrochemical and physical characterizations of the MWCNTs/pre‐PGE were investigated using cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) techniques. Under the optimized conditions, the linear working range was 0.030–200.0 μM with a limit of detection of 9.0 nM using the differential pulse adsorptive stripping voltammetry (DPAdSV) method. The proposed sensor exhibited good sensitivity, repeatability, reproducibility, and stability. The MWCNTs/pre‐PGE were successfully applied to L‐Try determination in commercial poly‐amino acid supplements with good recovery and accuracy.
Dopamine (DA), a critical catecholamine neurotransmitter, is responsible for normal functioning of body. Its dysregulation causes cognitive disturbances. Thus, an efficient real time monitoring of DA in clinical samples is required. Herein we report a novel nanocomposite comprising of carbon nanocoils (CNC) and copper tetra(p-methoxyphenyl)porphyrin (CuTMePP) for efficient electrochemical detection of dopamine that was characterized by FTIR, UV/vis., Raman, XRD, SEM, TEM and energy dispersive X-ray techniques. The electrochemical studies were performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy and differential pulse voltammetry (DPV). CNC/CuTMePP/glassy carbon (GC) has demonstrated two linear trends between current and concentration i.e. 0.1 to 100.0 µM and 100.0 to 800.0 µM. Limit of detection (LoD), limit of quantification (LoQ) and sensitivity of the electrode in the concentration range of 0.1 to 100.0 µM was 50.0 nM, 167.0 nM and 1.76 µAµM⁻¹cm⁻², respectively using CV. With DPV, the LoD, LoQ and sensitivity were found to be 64.0 nM, 211.0 nM and 0.75 µAµM⁻¹cm⁻², respectively obtained in a concentration range of 0.1 to 100.0 µM. The as prepared sensor exhibited good intra/inter-day stabilities, reproducibility, excellent recovery in the human serum samples, presented significant clinical dopamine detection and showed comparable results with other work in literature.
A sensitive scheme was established for the detection of vitamin C (Ascorbic acid) and vitamin B1 (Thiamin HCl) using Maltol capped AgNPs (McAgNPs) as colorimetric sensor. The designed scheme showed an instant alteration in color from yellow to orange and green for vitamin-C and vitamin B1 sequentially. The probe was sensitive in a concentration range of (0-1 µM) with limit of detection 0.064 and 0.038 µM for vitamin C and vitamin B1 sequentially. The interaction mechanism between vitamin C and vitamin B1 and McAgNPs was evaluated by visible spectroscopy, FTIR, and AFM. Vitamin C attaches on the surface of nanoparticles by C=O group, while OH, C-S-C, and NH2 groups are involved in the binding of vitamin B1 with McAgNPs. The Vit-C/Vit-B1-McAgNPs complexes were stable over a wide range of pHs. The size of McAgNPs increased after the interaction of vitamin C/vitamin B1 from 30-40 nm to 500 and 400 nm sequentially. The scheme was successfully applied for the detection of vitamin C and vitamin B1 in urine, plasma, water, and commercial pharmaceutical tablets with good recoveries. The scheme was ascertained to be more sensitive than many other formerly described schemes.
