Application of Gd2ZnMnO6/ZnO nanocomposite for electrochemical measurement of acetaminophen, diphenhydramine, and phenylephrine.

An electrochemical sensor with high sensitivity was designed and used to measure several drugs, including acetaminophen (AC), diphenhydramine (DPH), and phenylephrine (PHE). This sensor was created using a carbon paste electrode (CPE) that has been modified with a Gd2ZnMnO6/ZnO nanocomposite. In order to analyze the developed sensor, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) techniques were used. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, chronoamperometry, and apparent resistance spectroscopy methods. Also, the compound's diffusion coefficient (D) was calculated. By using the differential pulse voltammetry, AC, DPH, and PA were determined with detection limits of 2.5 × 10-8, 3.3 × 10-8, and 1.4 × 10-8 M in the linear concentration ranges of 0.09-900 µM. Finally, the designed sensor was utilized to measure the drug in real samples, and acceptable results were obtained.

Determination of methotrexate in plasma and environmental samples using an electrochemical sensor modified by UiO66-NH2/mesoporous carbon nitride composite and synergistic signal amplification with decorated AuNPs.

Electrochemical methods have low toxicity, fast response and, easy operation. By modifying electrochemical sensors with a conductive and porous modifier, their sensitivity and selectivity can be improved. Nanomaterials with new and extraordinary properties are a new approach in science and especially in electrochemical sensors. In this study, UiO66-NH2/mesoporous carbon nitride (M - C3N4) composite provides a porous structure for decorated Au nanoparticles (AuNPs) to prepare a potent modifier for carbon paste electrode (CPE). Due to environmental toxicity of methotrexate, its sensitive, fast and, low-cost determination in workplace environments is of great interest. So, the modified CPE was applied as a sensitivity analysis approach for methotrexate in plasma samples. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used as techniques to optimize the analysis and measurement of methotrexate. To measure this drug, several effective parameters were optimized and a calibration curve was drawn under optimal conditions. The calibration curve showed a linear range from 0.5 to 150 µM with a detection limit of 0.15 µM for methotrexate. Examining the repeatability of the response of one electrode and multiple electrodes under optimal conditions shows the high precision of the developed method. Finally, this developed method based on UiO66-NH2/M-gC3N4/AuNPs|CPE was used to determine the methotrexate in the plasma sample using the standard addition method.

Application of the C-C3N4/Li2CoMn3O8//IL nanocomposite for design a sensitive electrochemical sensor inorder to detection of cetirizine, acetaminophen and phenylephrine in biological and pharmaceuticals samples.

Due to the side effects of cetirizine overdose and the need to monitor its concentration in the human body, in this work, an electrochemical sensor has been prepared by utilizing a carbon paste electrode modified with Li2CoMn3O8/CC3N4 nanocomposite and ethyl-3-methyl-imidazolium chloride ionic liquid ([EMIM][Cl]) to determine cetirizine in the human blood serum sample and urine as well as drug samples. Li2CoMn3O8/CC3N4 nanocomposite was characterized by Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis. The investigation of the influence of each modifier component showed that the existence of all components in modification has a synergistic effect. Li2CoMn3O8/CC3N4/IL nanocomposite has a larger surface area relative to the components alone, thus providing a more fine-grained media to facilitate electron transfer during the reaction between analyte and electrode. Determination of cetirizine was performed in phosphate buffer solution with pH 7.0 and detection limits obtained in the concentration ranges of 0.03-0.9 and 3-300 µM was 11.8 × 10-9 M. The diffusion coefficient (D = 9.2 × 10-6 cm2s-1) of cetirizine at the surface of the modified electrode was determined by chronoamperometry. Finally, simultaneous detection of cetirizine, phenylephrine and acetaminophen was performed using the suggested sensor without any interference.

A nanoporous gold film sensor modified with polypyrrole/CuO nanocomposite for electrochemical determination of piroxicam and tramadole.

In this paper, an electrochemical sensor was developed to determine piroxicam (PX) and tramadole (Tr) based on their enhanced electrochemical responses at the surface of the polypyrrole/CuO nanocomposite-modified nanoporous gold film (NPGF) electrode. The experimental results showed that PX provide an oxidation peak at 0.65 V in pH = 8.0. The DPV results were linearly affiliated on PX concentration within the two closed windows (C1PX = 0.05-30.0 µM, correlation coefficient of 0.9905, and C2PX = 50.0-300.0 µM, correlation coefficient of 0.9927). From voltammetric curves, the detection limit (LOD = 3Sb/m) for PX at a surface of PPY-CuO-NPGF electrode was appeared to be 0.01 µM. Furthermore, the ability of PPY-CuO-NPGF electrode for simultaneous measurement of PX and Tr was investigated. The suggested sensor shows a long-time stability, good repeatability, and rapid response in the mixture media of PX and Tr.

Use of a nano-porous gold film electrode modified with chitosan / polypyrrole for electrochemical determination of metronidazole in the Presence of Acetaminophen.

This study, it was aimed to provide a sensitive, easy and selective method for designing Nano-porous gold film electrode (NPGF) electrode for simultaneous measurement of metronidazole (MT) and acetaminophen (AC). For this purpose, the NPGF electrode surface was modified with chitosan (CS) and poly pyrrole (PPY) by electrochemical method, and then CS and PPY modified NPGF (PPY-CS-NPGF) electrode were used to measure these drugs. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) are employed for the characterization of the attained PPY-CS-NPGF electrode. Using cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and chronoamperometry, the electrochemical behavior of MT was investigated with the modified electrode. By differential pulse voltammetry, linear ranges of concentration 0.005-100 µM with linear coefficients of 0.9898 and a detection limit of 0.0009 µM were obtained for MT. Finally, an electrochemical sensor was used to measure MT in a real sample, which yielded acceptable results. PPY-CS-NPGF electrodes have a wide linear range, high selectivity, sensitivity and stability and can be used successfully to determine these drugs.

A novel platform based on CoMn2O4-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode for voltammetric detection of pethidine in the presence morphine and olanzapine.

The present work focuses on the development of a new electrochemical platform based on CoMn2O4-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode (CoMn2O4-rGO/IL/CPE) for electrochemical determination of pethidine in the presence of biological species. For the first time, the electrooxidation mechanism of pethidine in presences of morphine and olanzapine is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technologies. The as-synthesized CoMn2O4-rGO nanocomposites are characterized by physicochemical measurements such as X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR). The obtained results illustrated synergistic interactions between rGO and CoMn2O4 structures. Also, to investigate the electrode charge-transfer resistances, electrochemical features of the resulting nanocomposites are studied via electrochemical impedance spectroscopy (EIS) analysis. Based on the result, three segmented linear ranges are observed over the range 0.08-900 µM and detection limit of 0.024 µM. Over the 10.0-40.0 µM ranges of pethidine in phosphate buffer solution (PBS-pH 7.0), suitable diffusion coefficient of 5.67 × 10-7 cm2 s-1 is evaluated by chronoamperometry technique (CHA). Finally, the CoMn2O4-rGO/IL/CPE with high sensitivity, selectivity and repeatability is successfully used for determination of pethidine in real sample and drug formulation.

Simultaneous determination of citalopram and selegiline using an efficient electrochemical sensor based on ZIF-8 decorated with RGO and g-C3N4 in real samples.

A novel carbon paste electrode (CPE) modified with ZIF-8/g-C3N4/RGO nanocomposite is used as a high sensitive electrochemical sensor to simultaneously determine citalopram (CIT) and selegiline (SEL). Simultaneous determination of these drugs is important because of their effect on the level of neurotransmitter serotonin in the central nervous system (CNS) which can happen by overuse and concurrent consumption. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) are used in order to investigate the electrochemical behavior of the electrode. Various techniques such as scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) are employed to affirm the structure of ZIF-8/g-C3N4/RGO nanocomposite. Excellent sensing performance of the suggested electrode is verified based on the low limit of detection of 0.008 µM and 0.014 µM which represent two linear ranges from 0.009 to 900 µM for CIT and 0.09-900 µM for SEL, respectively. The analytical performance of the proposed electrochemical sensor is investigated in real samples including human blood and urine with acceptable results.

A new strategy to design label-free electrochemical biosensor for ultrasensitive diagnosis of CYFRA 21-1 as a biomarker for detection of non-small cell lung cancer.

Lung cancer is one of the most dangerous cancers with high mortality rate among other cancers therefore, early detection of this cancer is very important. Many studies have been reported in ways of diagnostic lung cancer early. According to reports, one of the most important biomarkers to detect lung cancer is Cytokeratin 19 fragment 21-1 (CYFRA21-1), which is significantly related to non-small cell lung cancer, in particular, squamous cell carcinoma. Thus, finding a new method for the early diagnosis of CYFRA 21-1 (DNA target probe) is essential. In the present report, we design a novel label-free electrochemical DNA-biosensor related to the signal of guanine oxidation. The proposed DNA biosensor is fabricated by a modified glassy carbon electrode (GCE) with reduced-graphene oxide (rGO), poly pyrrole (PPy), silver nanoparticles (AgNPs) and single-strand DNA (ssDNA as capture probe) GCE/rGO/PPy/AgNPs/ssDNA. The differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques are used to verify the hybridization process between capture and target probes. Electrochemical impedance spectroscopy (EIS), energy diffraction X-ray (EDX) and field-emission scanning microscopy (FE-SEM) techniques are applied to the characterization of different modified GCE surfaces as well as X-ray diffraction (XRD) for graphene oxide synthesis. The XRD pattern of the synthesized GO that its diffraction peak appears at 10.2. The applied CV and DPV for the guanine oxidation are determined under optimal conditions. The label-free DNA biosensor showed a great result for the determination of CYFRA21-1 with a wide linear range from two consecutive linear relationships of peak current and CYFRA21-1 concentration were found (1.0 × 10-14 - 1.0 × 10-10 M, R2 = 0.9936 and 1.0 × 10-9 - 1.0 × 10-6 M, R2 = 0.9955). Proposed electrochemical biosensor displayed low detection limit (2.4 fM).

Determination of D&C Red 33 and Patent Blue V Azo dyes using an impressive electrochemical sensor based on carbon paste electrode modified with ZIF-8/g-C3N4/Co and ionic liquid in mouthwash and toothpaste as real samples.

Synthetic azo dyes are widely used in a variety of industries, but many of them pose a risk to human health, particularly when consumed in large quantities. As a result, their existence in products should be closely monitored. D&C red 33 and Patent Blue V are mostly used in cosmetics, especially in toothpaste and mouthwashes. A novel carbon paste electrode modified with ZIF-8/g-C3N4/Co nanocomposite and 1-methyl-3-butylimidazolium bromide as an ionic liquid was employed as a highly sensitive reproducible electrochemical sensor for the simultaneous determination of these common dyes. ZIF structure has unique properties such as high surface area, suitable conductivity, and excellent porosity. The electrochemical behavior of the suggested electrode was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). To characterize the synthesized nanocomposites, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were applied to investigate the structure of nanocomposites. Under the optimized conditions, the modified sensor offered a wide linear concentration range 0.08-10 µM (R2 = 0.9906) and 10-900 µM (R2 = 0.9932) with a low limit of detection of 0.034 µM. The value of diffusion coefficient (D), and the electron transfer coefficient (α) was calculated to be 310 × 10-5, and 0.9 respectively. This technique offered a successful performance for the determination of target analyte in the real samples with acceptable results between 96% and 107%.

Fabrication of a sensitive sensor for electrochemical detection of diltiazem in presence of methyldopa.

Diltiazem (DTZ) is one of the most important drugs in blood pressure that is used to treat cardiovascular diseases. With this overuse of this drug and its use for suicide, swelling and neck cramps and fever has made it important to measure it. So, this paper will give an account of modification of carbon paste electrode with the ternary-nanocomposite including reduced-graphene oxide (rGO), cadmium oxide and 1-ethyl 3- methyl imidazole chloride as ionic liquid for using the determination of DTZ in blood serum samples. Characterization of the synthesized rGO, cadmium oxide, and modified electrodes and their electrochemical performance were studied by, scanning electron microscopy, and X-ray diffraction, electrochemical impedance spectroscopy, and voltammetry technique. The improvement of the DTZ oxidation current by modified electrode originated from the increased electrode surface area. The optimized method was validated and the results showed that LOD = 3 nM and good linearity. Also, a linear concentration range of 0.01-150 µM with a LOD of 0.03 µM in presence methyldopa were achieved based on the electrochemical investigations. The prepared sensor showed good repeatability (RSD = 2.26%) and selectivity for DTZ determination in the real samples (relative recovery of 93-102%).

Development of an amplified nanostructured electrochemical sensor for the detection of cefixime in pharmaceuticals and biological samples.

As one of the third generation of cephalosporin category, cefixime has a considerable activity towards both gram-positive and gram-negative bacteria so the quantitative analysis is considerable. Based on the synthesized reduced graphene oxide/CoFe2O4/ionic liquid (IL) (1-Ethyl-3-Methylimidazolium) (IL/CoFe2O4/rGO) nanocomposite, a modified carbon paste electrode (CPE) was selected as a sensor for determining cefixime. The structure and ability of nanostructures are investigated by various techniques containing scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CHA). The suggested sensor was successfully used for the simultaneous determination of cefixime, mefenamic acid, and acetaminophen. Under optimized settings, the oxidation peak current was obtained in the two linear ranges from 0.06 to 10 µM (0.02-4.53 µg.ml-1) (R2 = 0.9909) and 10.0-700.0 µM (4.53-317.394 µg.ml-1) (R2 = 0.9970) along with the detection limit of cefixime 0.035 µM (0.015 µg.ml-1). The values of electro-transfer coefficient (α) and diffusion coefficient (D) were achieved 0.9 and 1.17 × 10-6 cm2s-1. The electro-oxidation of cefixime occurs at an approximate potential of 0.85 V with an irreversible oxidation peak. The F-test (precision) and t-test (accuracy) were used for comparing the obtained results in urine samples. The proposed modified electrode shows high performance for the analysis of cefixime, mefenamic acid, and acetaminophen in pharmaceuticals and biological samples with good results.

Introducing of Li2FeMn3O8 /C-C3N4 /IL nanocomposite for electrochemical determination of pantoprazole sodium in real samples.

A new electrochemical sensor based on Li2FeMn3O8/C-C3N4 (LFMO/CCN)/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode (CPE) has been constructed to measure pantoprazole sodium (PNZS). The electrochemical impedance spectroscopy (EIS) method was employed to evaluate the electrode charge-transfer resistances. Moreover, the differential pulse voltammetry method was used to detect PNZS in phosphate buffer solution (PBS) at pH 7.0. The detection limit of 80.0 × 10-9 M and 10.9 × 10-7 M was obtained under optimal conditions in the linear concentration range of PNZS 0.09-100 µM and 100-900 µM. Chronoampermetry technique was utilized to determine the diffusion coefficient (D) of PNZS on the modified electrode surface. The CCN/LFMO/IL/CPE was successfully used to determine PNZS in various drug formulations such as tablets and vials. Finally, simultaneous determination of PNZS and acetaminophen was accomplished with no interference based on the proposed sensor.

Novel enzymatic graphene oxide based biosensor for the detection of glutathione in biological body fluids.

In this work, we report a novel enzymatic biosensor based on glutathione peroxidase (GSH-Px), graphene oxide (GO) and nafion for the electrochemical sensing of glutathione (GSH) in body fluids. GSH-Px was immobilized covalently via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto modified glassy carbon electrode (GCE) decorated with GO and nafion and successfully used for sensing of GSH in the presence of H2O2 as catalyst with Michaelis-Menten constant about 0.131 mmol/L. The active surface are of GCE improve from 0.183 cm2 to 0.225 cm2 after modification with GO. The introduced biosensor (GSH-Px/GO/nafion/GCE) was used for monitoring of GSH over the range 0.003-370.0 µM, with a detection limit of 1.5 nM using differential pulse voltammetric (DPV) method. The GSH-Px/GO/nafion/GCE was successfully applied to the determination of GSH in real samples.

The potential of electrochemistry for one-pot and sensitive analysis of patent blue V, tartrazine, acid violet 7 and ponceau 4R in foodstuffs using IL/Cu-BTC MOF modified sensor.

Since excessive use of synthetic dyes has negative effects on human health, their determination in foodstuff is necessary. A sensitive sensor was developed based on copper BTC metal-organic framework (Cu-BTC MOF) and 1-ethyl-3-methylimidazolium chloride as an ionic liquid (IL) in an attempt to modify the carbon paste electrode and to improve the active surface area and electric conductivity so that electron transfer is faster for electro analysis. For the first time, high sensitivity, excellent conductivity, and appropriate selectivity of the electrochemical sensor have been evaluated as a new study for simultaneous determination of tartrazine, patent blue V, acid violet 7 and ponceau 4R. Excellent sensing performance of the proposed electrode was confirmed for patent blue V as an outstanding sensor, according to the low limit of detection of 0.07 µM, with a wide linear concentration range of 0.08 to 900 µM and reasonable recovery. In order to characterize the electrochemical behavior of electrode, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy are used. Various techniques such as scanning electron microscopy (SEM) with energy dispersive X-Ray analysis (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) are employed to verify the structure of copper BTC metal-organic framework. The results revealed close packing of hierarchically porous nanoparticles and crystal structure of Cu-BTC MOF, with the edge of each particle around 20-37 nm. The analytical performance of the suggested electrochemical sensor is acceptable in foodstuffs such as jellies, condiments, soft drinks, and candies.

A critical review on the use of potentiometric based biosensors for biomarkers detection.

Potentiometric-based biosensors have the potential to advance the detection of several biological compounds and help in early diagnosis of various diseases. They belong to the portable analytical class of biosensors for monitoring biomarkers in the human body. They contain ion-sensitive membranes sensors can be used to determine potassium, sodium, and chloride ions activity while being used as a biomarker to gauge human health. The potentiometric based ion-sensitive membrane systems can be coupled with various techniques to create a sensitive tool for the fast and early detection of cancer biomarkers and other critical biological compounds. This paper discusses the application of potentiometric-based biosensors and classifies them into four major categories: photoelectrochemical potentiometric biomarkers, potentiometric biosensors amplified with molecular imprinted polymer systems, wearable potentiometric biomarkers and light-addressable potentiometric biosensors. This review demonstrated the development of several innovative biosensor-based techniques that could potentially provide reliable tools to test biomarkers. Some challenges however remain, but these can be removed by coupling techniques to maximize the testing sensitivity.

Enhanced Supercapacitor Performance Using a Co3 O4 @Co3 S4 Nanocomposite on Reduced Graphene Oxide/Ni Foam Electrodes.

To avoid an enormous energy crisis in the not-too-distant future, it be emergent to establish high-performance energy storage devices such as supercapacitors. For this purpose, a three-dimensional (3D) heterostructure of Co3 O4 and Co3 S4 on nickel foam (NF) that is covered by reduced graphene oxide (rGO) has been prepared by following a facile multistep method. At first, rGO nanosheets are deposited on NF under mild hydrothermal conditions to increase the surface area. Subsequently, nanowalls of cobalt oxide are electro-deposited on rGO/Ni foam by applying cyclic-voltammetry (CV) under optimized conditions. Finally, for the synthesis of Co3 O4 @Co3 S4 nanocomposite, the nanostructure of Co3 S4 was fabricated from Co3 O4 nanowalls on rGO/NF by following an ordinary hydrothermal process through the sulfurization for the electrochemical application. The samples are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The obtained sample delivers a high capacitance of 13.34 F cm-2 (5651.24 F g-1 ) at a current density of 6 mA cm-2 compared to the Co3 O4 /rGO/NF electrode with a capacitance of 3.06 F cm-2 (1230.77 F g-1 ) at the same current density. The proposed electrode illustrates the superior electrochemical performance such as excellent specific energy density of 85.68 W h Kg-1 , specific power density of 6048.03 W kg-1 and a superior cycling performance (86% after 1000 charge/discharge cycles at a scan rate of 5 mV s-1 ). Finally, by using Co3 O4 @Co3 S4 /rGO/NF and the activated carbon-based electrode as positive and negative electrodes, respectively, an asymmetric supercapacitor (ASC) device was assembled. The fabricated ASC provides an appropriate specific capacitance of 79.15 mF cm-2 at the applied current density of 1 mA cm-2 , and delivered an energy density of 0.143 Wh kg-1 at the power density of 5.42 W kg-1 .

Preparation and study of characteristics of LiCoO2/Fe3O4/Li2B2O4 nanocomposites as ideal active materials for electrochemical hydrogen storage.

The nanocomposites of LiCoO2/Fe3O4/Li2B2O4 were designed by the Pechini route using different fuels for the optimization of their morphology and structure. Compared to other fuels, citric acid can act as both an ideal fuel and a capping agent. The ratio of the EG : H2O mixture is another parameter, which was studied in terms of its effects on the structural characterization. The optimized sample with a rod shape was selected to compare with the bulk sample through electrochemical hydrogen storage capacity. The discharge capacity for rod-shaped nanocomposites measured was 1284 mA h g-1. However, the discharge capacity for the bulk morphology was calculated to be about 694 mA h g-1. The magnetic, electrochemical and structural analyses were performed to investigate the properties of LiCoO2/Fe3O4/Li2B2O4 nanocomposites.

NiFe2O4-rGO/ionic liquid modified carbon paste electrode: An amplified electrochemical sensitive sensor for determination of Sunset Yellow in the presence of Tartrazine and Allura Red.

In this paper, using a carbon paste electrode (CPE) modified with 1-ethyl-3-methylimidazolium chloride as an ionic liquid (IL) and NiFe2O4-rGO nanocomposite (IL/NiFe2O4/rGO/CPE), a sensitive and effective electrochemical sensor is applied to analyze Sunset Yellow. The X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) and Fourier-transform infrared spectroscopy (FTIR) are employed to characterize the synthesized NiFe2O4-rGO nanocomposite. The oxidation peak currents of colorants were obtained by CV and DPV techniques; and as a result, the two linear ranges from 0.05 to 30 µM (R2 = 0.9939) and 30 to 500 µM (R2 = 0.9953) along with LOD of 0.03 µM for Sunset Yellow is obtained. The proposed sensor is successfully applied to determine the Sunset Yellow, Tartrazine and Allura Red in PBS (pH 3). The IL/NiFe2O4/rGO/CPE displays a high performance for analysis of these dyes in hair shampoo and an orange juice as real samples with acceptable results.

Analysis of glutathione in the presence of acetaminophen and tyrosine via an amplified electrode with MgO/SWCNTs as a sensor in the hemolyzed erythrocyte.

In this study, we investigated the effect of adding MgO/SWCNTs and 2-Chloro-N'-[1-(2,5-dihydroxyphenyl) methylidene]aniline (2-CDHPMA) to a carbon paste matrix, which could act as a voltammetric sensor for the analysis of glutathione. The electrocatalytic interaction between 2-CDHPMA and glutathione was used as a factor for the analysis of this biological compound in real samples. In addition, the presence of MgO/SWCNTs can help in increasing the sensitivity of the fabricated sensor and for obtaining a low limit of detection in the analysis of glutathione. When the carbon-paste electrode was amplified with MgO/SWCNTs and 2-CDHPMA (CPE/MgO/SWCNTs/2-CDHPMA), it showed a good selectivity for the analysis of glutathione in the presence of acetaminophen and tyrosine with the separated peak potentials at ~ 280mV, ~ 570mV, and ~ 880mV for the first time. We detected a linear dynamic range between 0.05 and 700.0µmolL-1 with the limit of detection set at ~ 10 ± 0.3nmolL-1 for the analysis of glutathione by the square-wave voltammetric method. The CPE/MgO/SWCNTs/2-CDHPMA showed a high quality of detection of glutathione in the hemolyzed erythrocyte sample.

An electrochemical strategy to determine thiosulfate, 4-chlorophenol and nitrite as three important pollutants in water samples via a nanostructure modified sensor.

A voltammetric sensor was designed to analyze thiosulfate (TS), 4-chlorophenol (4-CP) and nitrite (NT), which are water pollutants, in mixed samples by combining the high conductive properties of NiO nanoparticle (NiO/NPs) and the excellent mediator properties of novel catechol derivative (2,4-dimethyl-N'-[1-(2,3-dihydroxyphenyl)methylidene]aniline). 2,4-Dimethyl-N'-[1-(2,3-dihydroxyphenyl)methylidene]aniline was synthesized for the first time and proposed as a high-quality modifier for electrocatalytic analysis of TS and its simultaneous analysis in the presence of 4-CP and NT. At a pH=6.0 as an optimum condition in electrochemical analysis, we seen the synergic effect for the simultaneous determination of TS, 4-CP and NT in the range of 0.05-400.0µM, 1.0-600.0µM, and 10.0-700.0µM, with a limit of detection of 0.01µM for TS, of 0.7µM for 4-CP, and of 5.0µM for NT respectively.