L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for...L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for the modification of a glassy carbon electrode (GCE), for the sensitive detection of L-tryptophan (Trp). After spectroscopic and morphological characterization of the extracted NFC, the GC electrode modification was monitored through cyclic voltammetry. The NFC-modified electrode exhibited good analytical performance in detecting Trp with a wide linear range between 7.5 × 10−4 mM and 10−2 mM, a detection limit of 0.2 µM, and a high sensitivity of 140.0 µA∙mM−1. Additionally, the NFC/GCE showed a good reproducibility, good selectivity versus other amino acids, uric acid, ascorbic acid, and good applicability to the detection of Trp in urine samples.展开更多
Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems,supporting electrolytes and pH using differential paise,square-wave and cyclic voltammetry.Based on its reduction behavior...Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems,supporting electrolytes and pH using differential paise,square-wave and cyclic voltammetry.Based on its reduction behavior,a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage.Three welldefined peaks were observed in 0.1% SLS,Britton-Robinson (BR) buffer of pH 2.5.The effect of surfaetants like sodium lauryl sulfate (SLS),cetyl trimethyl ammonium bromide (CTAB) and Tween 20 was studied.Among these surfactants SLS showed significant enhancement in reduction peak.The cathodic peak currents were directly proportional to the concentration of midazolam with correlation coetfficient of 0.99.展开更多
For the first time, sulfanilamide(SFD) was determined in otologic solution, human urine and serum by electroanalytical techniques on glassy carbon electrode(GCE). The cyclic voltammetry(CV) experiments showed an irrev...For the first time, sulfanilamide(SFD) was determined in otologic solution, human urine and serum by electroanalytical techniques on glassy carbon electrode(GCE). The cyclic voltammetry(CV) experiments showed an irreversible oxidation peak at t 1.06 V in 0.1 mol/L BRBS(p H ? 2.0) at 50 m V/s. Different voltammetric scan rates(from 10 to 250 m V/s) suggested that the oxidation of SFD on the GCE was a diffusioncontrolled process. Square-wave voltammetry(SWV) method under optimized conditions showed a linear response to SFD from 5.0 to 74.7 μmol/L(R ? 0.999) with detection and quantification limits of 0.92 and3.10 μmol/L, respectively. The developed SWV method showed better results for detection limit and linear range than the chronoamperometry method. It has been successfully applied to determine SFD concentration in pharmaceutical formulation, human urine and serum samples with recovery close to 100%.展开更多
A voltammetric sensor based on the electropolymerization of cobalt-poly(methionine)(Co-poly(Met)) on a glassy carbon electrode (GCE) was developed and applied for the determination of estriol by differential pulse vol...A voltammetric sensor based on the electropolymerization of cobalt-poly(methionine)(Co-poly(Met)) on a glassy carbon electrode (GCE) was developed and applied for the determination of estriol by differential pulse voltammetry (DPV) for the first time. The electrochemical properties of the Co-poly(Met)/GCE were analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the polymers on the GCE surface. The deposition of the Co-poly(Met) film on the GCE surface enhanced the sensor electronic transfer. CV studies revealed that estriol exhibits an irreversible oxidation peak at t0.58 V for the Co-poly(Met)/GCE (vs. Ag/AgCl reference electrode) in 0.10 mol/L Britton-Robinson buffer solution (pH=7.0). Different voltammetric scan rates (10-200 mV/s) suggested that the estriol oxidation on the Co-poly(Met)/GCE surface is controlled by adsorption and diffusion processes. Based on the optimized DPV conditions, the linear responses for estriol quantification were from 0.596 μmol/L to 4.76 μmol/L (R2 =0.996) and from 5.66 μmol/L to 9.90 μmol/L (R2 =0.994) with a limit of detection (LOD) of 0.0340 μmol/L and a limit of quantification (LOQ) of 0.113 μmol/L. The DPV-Co-poly(Met)/GCE method provided good intra-day and inter-day repeatability with RSD values lower than 5%. Also, no interference of real sample matrices was observed on the estriol voltammetric response, making the DPV-Copoly( Met)/GCE highly selective for estriol. The accuracy test showed that the estriol recovery was in the ranges 96.7%-103% and 98.7%-102% for pharmaceutical tablets and human urine, respectively. The estriol quantification in pharmaceutical tablets performed by the Co-poly(Met)/GCE-assisted DPV method was comparable to the official analytical protocols.展开更多
Nano-gold (NG) modified glassy carbon electrodes (GCEs) were used for determination of epinephrine (EP) in the presence of high concentration ascorbic acid (AA) by cyclic voltammetry (CV). This modified electrode can...Nano-gold (NG) modified glassy carbon electrodes (GCEs) were used for determination of epinephrine (EP) in the presence of high concentration ascorbic acid (AA) by cyclic voltammetry (CV). This modified electrode can not only catalytically oxidize EP and AA, but also separate the catalytic peak potentials of EP and AA by about 183.5 mV. In pH = 7.0 ogisogate byffer solution, the linear range of epinephrine was 5 106 ~ 1 ?10-4 mol/L.展开更多
The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0....The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0' of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Km^app) was 2.95 mmol/L.展开更多
A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with...A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.展开更多
The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at b...The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small. However, when the electrode was activated at certain potential (i.e. 1.9 V) or modified with carbon nanotube, the peak became more sensitive, resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3×10^-7 - 1.1×10^-5 mol/L at activated glassy carbon electrode and in the range of 1.0×10^-5 - 5.0×10^-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0.998 and 0.997, respectively. The determination limit was 1.0×10^-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.展开更多
The glassy carbon (GC) electrode modified with a monolayer nickel hydroxide (GC/Ni(OH) 2) was prepared by immersion of GC substrate in 1.0×10 -3 mol/L NiSO 4 solution, and then cyclic voltammetric scannin...The glassy carbon (GC) electrode modified with a monolayer nickel hydroxide (GC/Ni(OH) 2) was prepared by immersion of GC substrate in 1.0×10 -3 mol/L NiSO 4 solution, and then cyclic voltammetric scanning in 0.20 mol/L KOH. Similarly, GC/Co(OH) 2 electrode was prepared too. The experiments showed that the voltammetric behavior of GC/Ni(OH) 2 electrode in 0.20 mol/L KOH is more stable than that of GC/ Co(OH) 2. It was found that the GC/Ni(OH) 2 electrode acts as an effective electrocatalysis for the oxidation of hydrazine.展开更多
The present study reports voltammetric reduction of nitazoxanide in Britton-Robinson (B-R) buffer by cyclic and square-wave voltammetry at glassy carbon electrode. A versatile fully validated voltammetric method for...The present study reports voltammetric reduction of nitazoxanide in Britton-Robinson (B-R) buffer by cyclic and square-wave voltammetry at glassy carbon electrode. A versatile fully validated voltammetric method for quantitative determination of nitazoxanide in pharmaceutical formulation has been proposed. A squrewave peak current was linear over the nitazoxanide concentration in the range of 20-140 ~tg/mL. The limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 5.23 la~/mL and 17.45 la~/mL, respectively.展开更多
Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be ...Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be adsorbed on the electrode surface in the presence of an excess of copper(Ⅱ). After accumulation period, hypoxanthine Cu + was stripped from the electrode surface and the anodic current coming near to the oxidation of Cu(Ⅰ) to Cu(Ⅱ) was measured. A linear calibration curve in the range of 5 nmol/L 1.5 mmol/L hypoxanthine, with a detection limit of 0.5 nmol/L hypoxanthine were obtained.展开更多
Hand, foot, and mouth disease (HFMD) is a common infectious disease in children, occurring primarily in preschool children[1_3] with infants under three years old being gen erally susceptible. The disease is caused by...Hand, foot, and mouth disease (HFMD) is a common infectious disease in children, occurring primarily in preschool children[1_3] with infants under three years old being gen erally susceptible. The disease is caused by various enteroviruses, among which EV71 and Coxsackievirus A group 16 (Cox A16) are the most comm on ⑷.According to in formation released by the Chinese Center for Disease Control and Prevention on June 8, 2016, EV71 infection- related HFMD has been prevalent among infants and young children in China since 2007, with a high incidenee and many deaths.展开更多
In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse...In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse stripping voltanunetry was applied for determing MBC in grains. The detection limit is 4×10-8mo/L.The recovery is from 91.3% to 95.7%. The method has advantages of simplicity and high sensitivity.展开更多
A reversible electron transfer between horse heart cytochrome c and a bare glassy carbon electrode was found and the dependence of direct electrochemical behaviotw on the electrode surface state was discussed.
The electrochemical behavior of paclitaxel drug was studied at a glassy carbon electrode in phosphate buffer solutions using cyclic and differential-pulse voltammetric techniques.The oxidation process was shown to be ...The electrochemical behavior of paclitaxel drug was studied at a glassy carbon electrode in phosphate buffer solutions using cyclic and differential-pulse voltammetric techniques.The oxidation process was shown to be irreversible over the pH range(3.0e10.4)and was diffusion controlled.Effects of anodic peak potential(E_(p)),anodic peak current(Ipa),scan rate,pH,heterogeneous rate constant(k^(0)),etc have been discussed.A possible electrooxidation mechanism was proposed.An analytical method was developed for the determination of paclitaxel in phosphate buffer solution at pH¼7.0 as a supporting electrolyte.The anodic peak current varied linearly with paclitaxel concentration in the range 1.0×10^-(6)M to 1.0×10^-(5)M with a limit of detection(LOD)of 1.23×10^(-8)M and limit of quantification(LOQ)of 4.10×10^(-8)M.The proposed method was successfully applied to the determination of paclitaxel in pure and real samples.展开更多
A simple and rapid method was developed using cyclic, differential pulse and square wave voltammetric techniques for the determination of trace-level chalcone at a glassy carbon electrode. Chalcone could produce two a...A simple and rapid method was developed using cyclic, differential pulse and square wave voltammetric techniques for the determination of trace-level chalcone at a glassy carbon electrode. Chalcone could produce two anodic peaks at about 0.514 V and 1.478 V and a cathodic peak at about -0.689 V. The differential pulse voltammerty presents a good linear response as compared to square wave voltammetry in the range of 0.2 - 10 μM with a detection limit of 0.18 μM. The proposed method was used successfully for its quantitative determination in spiked human plasma and urine as real samples.展开更多
In this study, the electrochemical oxidation of CT (catechol), HQ (hydroquinone) and RS (resorcinol) was investigated using cyclic and linear sweep voltammetries at GCE (glassy carbon electrode). The GCE showe...In this study, the electrochemical oxidation of CT (catechol), HQ (hydroquinone) and RS (resorcinol) was investigated using cyclic and linear sweep voltammetries at GCE (glassy carbon electrode). The GCE showed an excellent electro activity and reversibility towards the oxidation of these isomers at different conditions. HQ and CT showed one defined oxidation peak and one defined reduction peak while RS showed one defined oxidation peak. These isomers were determined also in their binary and tertiary mixtures. The calibration curves for CT, HQ and RS were obtained in the ranges of 5 × 10-6 to 1 × 10-3 mol.dm-3, 5 × 10-6 to 5 × 10-4mol.dm-3 and 1 × 10-5 to 1× 10-3 mol.dm-3, respectively. The detection limits were 9 ×10-7, 3 × 10-7, 6 × 10-6 mol.dm3 for CT, HQ and RS, respectively. At the optimal experimental conditions, these isomers were determined in different water samples. Also, the removal of catechol from aqueous solution by adsorption on activated charcoal and alumina was studied. After 24 h, 88.7% and 65.9% of catechol was removed using charcoal and alumina, respectively.展开更多
文摘L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for the modification of a glassy carbon electrode (GCE), for the sensitive detection of L-tryptophan (Trp). After spectroscopic and morphological characterization of the extracted NFC, the GC electrode modification was monitored through cyclic voltammetry. The NFC-modified electrode exhibited good analytical performance in detecting Trp with a wide linear range between 7.5 × 10−4 mM and 10−2 mM, a detection limit of 0.2 µM, and a high sensitivity of 140.0 µA∙mM−1. Additionally, the NFC/GCE showed a good reproducibility, good selectivity versus other amino acids, uric acid, ascorbic acid, and good applicability to the detection of Trp in urine samples.
文摘Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems,supporting electrolytes and pH using differential paise,square-wave and cyclic voltammetry.Based on its reduction behavior,a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage.Three welldefined peaks were observed in 0.1% SLS,Britton-Robinson (BR) buffer of pH 2.5.The effect of surfaetants like sodium lauryl sulfate (SLS),cetyl trimethyl ammonium bromide (CTAB) and Tween 20 was studied.Among these surfactants SLS showed significant enhancement in reduction peak.The cathodic peak currents were directly proportional to the concentration of midazolam with correlation coetfficient of 0.99.
基金UFESCNPq,CAPES(23068719374/2017-70)FAPES(54693900/2011,54694442/2011,60125730/2012,53671880/2011)for the financial support
文摘For the first time, sulfanilamide(SFD) was determined in otologic solution, human urine and serum by electroanalytical techniques on glassy carbon electrode(GCE). The cyclic voltammetry(CV) experiments showed an irreversible oxidation peak at t 1.06 V in 0.1 mol/L BRBS(p H ? 2.0) at 50 m V/s. Different voltammetric scan rates(from 10 to 250 m V/s) suggested that the oxidation of SFD on the GCE was a diffusioncontrolled process. Square-wave voltammetry(SWV) method under optimized conditions showed a linear response to SFD from 5.0 to 74.7 μmol/L(R ? 0.999) with detection and quantification limits of 0.92 and3.10 μmol/L, respectively. The developed SWV method showed better results for detection limit and linear range than the chronoamperometry method. It has been successfully applied to determine SFD concentration in pharmaceutical formulation, human urine and serum samples with recovery close to 100%.
基金CNPq (454438/2014-1)CAPES+1 种基金FINEPFAPEMIG for the financial support to this work
文摘A voltammetric sensor based on the electropolymerization of cobalt-poly(methionine)(Co-poly(Met)) on a glassy carbon electrode (GCE) was developed and applied for the determination of estriol by differential pulse voltammetry (DPV) for the first time. The electrochemical properties of the Co-poly(Met)/GCE were analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the polymers on the GCE surface. The deposition of the Co-poly(Met) film on the GCE surface enhanced the sensor electronic transfer. CV studies revealed that estriol exhibits an irreversible oxidation peak at t0.58 V for the Co-poly(Met)/GCE (vs. Ag/AgCl reference electrode) in 0.10 mol/L Britton-Robinson buffer solution (pH=7.0). Different voltammetric scan rates (10-200 mV/s) suggested that the estriol oxidation on the Co-poly(Met)/GCE surface is controlled by adsorption and diffusion processes. Based on the optimized DPV conditions, the linear responses for estriol quantification were from 0.596 μmol/L to 4.76 μmol/L (R2 =0.996) and from 5.66 μmol/L to 9.90 μmol/L (R2 =0.994) with a limit of detection (LOD) of 0.0340 μmol/L and a limit of quantification (LOQ) of 0.113 μmol/L. The DPV-Co-poly(Met)/GCE method provided good intra-day and inter-day repeatability with RSD values lower than 5%. Also, no interference of real sample matrices was observed on the estriol voltammetric response, making the DPV-Copoly( Met)/GCE highly selective for estriol. The accuracy test showed that the estriol recovery was in the ranges 96.7%-103% and 98.7%-102% for pharmaceutical tablets and human urine, respectively. The estriol quantification in pharmaceutical tablets performed by the Co-poly(Met)/GCE-assisted DPV method was comparable to the official analytical protocols.
基金The authors gratefully acknowledge financial support from the Natural Science Foundation of Anhui Province and the Natural Science Foundation of Anhui Education Committee.
文摘Nano-gold (NG) modified glassy carbon electrodes (GCEs) were used for determination of epinephrine (EP) in the presence of high concentration ascorbic acid (AA) by cyclic voltammetry (CV). This modified electrode can not only catalytically oxidize EP and AA, but also separate the catalytic peak potentials of EP and AA by about 183.5 mV. In pH = 7.0 ogisogate byffer solution, the linear range of epinephrine was 5 106 ~ 1 ?10-4 mol/L.
基金Supported by the National Natural Science Foundation of China(No.20605009)
文摘The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0' of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Km^app) was 2.95 mmol/L.
文摘A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.
文摘The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small. However, when the electrode was activated at certain potential (i.e. 1.9 V) or modified with carbon nanotube, the peak became more sensitive, resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3×10^-7 - 1.1×10^-5 mol/L at activated glassy carbon electrode and in the range of 1.0×10^-5 - 5.0×10^-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0.998 and 0.997, respectively. The determination limit was 1.0×10^-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.
文摘The glassy carbon (GC) electrode modified with a monolayer nickel hydroxide (GC/Ni(OH) 2) was prepared by immersion of GC substrate in 1.0×10 -3 mol/L NiSO 4 solution, and then cyclic voltammetric scanning in 0.20 mol/L KOH. Similarly, GC/Co(OH) 2 electrode was prepared too. The experiments showed that the voltammetric behavior of GC/Ni(OH) 2 electrode in 0.20 mol/L KOH is more stable than that of GC/ Co(OH) 2. It was found that the GC/Ni(OH) 2 electrode acts as an effective electrocatalysis for the oxidation of hydrazine.
文摘The present study reports voltammetric reduction of nitazoxanide in Britton-Robinson (B-R) buffer by cyclic and square-wave voltammetry at glassy carbon electrode. A versatile fully validated voltammetric method for quantitative determination of nitazoxanide in pharmaceutical formulation has been proposed. A squrewave peak current was linear over the nitazoxanide concentration in the range of 20-140 ~tg/mL. The limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 5.23 la~/mL and 17.45 la~/mL, respectively.
文摘Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be adsorbed on the electrode surface in the presence of an excess of copper(Ⅱ). After accumulation period, hypoxanthine Cu + was stripped from the electrode surface and the anodic current coming near to the oxidation of Cu(Ⅰ) to Cu(Ⅱ) was measured. A linear calibration curve in the range of 5 nmol/L 1.5 mmol/L hypoxanthine, with a detection limit of 0.5 nmol/L hypoxanthine were obtained.
基金supported by the China Mega-Project for Infectious Diseases of the Ministry of Science and Technology and Ministry of Health of the People’s Republic of China [2018ZX10201002]a grant from Science and Technology Department of Hubei Province [2018CFB630]a grant from the ‘ChuTian Scholar’ Project Award,Hubei Province,China
文摘Hand, foot, and mouth disease (HFMD) is a common infectious disease in children, occurring primarily in preschool children[1_3] with infants under three years old being gen erally susceptible. The disease is caused by various enteroviruses, among which EV71 and Coxsackievirus A group 16 (Cox A16) are the most comm on ⑷.According to in formation released by the Chinese Center for Disease Control and Prevention on June 8, 2016, EV71 infection- related HFMD has been prevalent among infants and young children in China since 2007, with a high incidenee and many deaths.
文摘In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse stripping voltanunetry was applied for determing MBC in grains. The detection limit is 4×10-8mo/L.The recovery is from 91.3% to 95.7%. The method has advantages of simplicity and high sensitivity.
文摘A reversible electron transfer between horse heart cytochrome c and a bare glassy carbon electrode was found and the dependence of direct electrochemical behaviotw on the electrode surface state was discussed.
基金One of the author(J.I.Gowda)thanks UGC,New Delhi,for the award of Research Fellowship in Science for Meritorious Stu-dents(RFSMS).
文摘The electrochemical behavior of paclitaxel drug was studied at a glassy carbon electrode in phosphate buffer solutions using cyclic and differential-pulse voltammetric techniques.The oxidation process was shown to be irreversible over the pH range(3.0e10.4)and was diffusion controlled.Effects of anodic peak potential(E_(p)),anodic peak current(Ipa),scan rate,pH,heterogeneous rate constant(k^(0)),etc have been discussed.A possible electrooxidation mechanism was proposed.An analytical method was developed for the determination of paclitaxel in phosphate buffer solution at pH¼7.0 as a supporting electrolyte.The anodic peak current varied linearly with paclitaxel concentration in the range 1.0×10^-(6)M to 1.0×10^-(5)M with a limit of detection(LOD)of 1.23×10^(-8)M and limit of quantification(LOQ)of 4.10×10^(-8)M.The proposed method was successfully applied to the determination of paclitaxel in pure and real samples.
文摘A simple and rapid method was developed using cyclic, differential pulse and square wave voltammetric techniques for the determination of trace-level chalcone at a glassy carbon electrode. Chalcone could produce two anodic peaks at about 0.514 V and 1.478 V and a cathodic peak at about -0.689 V. The differential pulse voltammerty presents a good linear response as compared to square wave voltammetry in the range of 0.2 - 10 μM with a detection limit of 0.18 μM. The proposed method was used successfully for its quantitative determination in spiked human plasma and urine as real samples.
文摘In this study, the electrochemical oxidation of CT (catechol), HQ (hydroquinone) and RS (resorcinol) was investigated using cyclic and linear sweep voltammetries at GCE (glassy carbon electrode). The GCE showed an excellent electro activity and reversibility towards the oxidation of these isomers at different conditions. HQ and CT showed one defined oxidation peak and one defined reduction peak while RS showed one defined oxidation peak. These isomers were determined also in their binary and tertiary mixtures. The calibration curves for CT, HQ and RS were obtained in the ranges of 5 × 10-6 to 1 × 10-3 mol.dm-3, 5 × 10-6 to 5 × 10-4mol.dm-3 and 1 × 10-5 to 1× 10-3 mol.dm-3, respectively. The detection limits were 9 ×10-7, 3 × 10-7, 6 × 10-6 mol.dm3 for CT, HQ and RS, respectively. At the optimal experimental conditions, these isomers were determined in different water samples. Also, the removal of catechol from aqueous solution by adsorption on activated charcoal and alumina was studied. After 24 h, 88.7% and 65.9% of catechol was removed using charcoal and alumina, respectively.