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Simultaneous determination of three 5-nitroimidazoles in foodstuffs by differential pulse voltammetry and chemometrics

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Chinese Chemical Letters 2011年第5期22卷 591-594页

作者： Yi Gui Yong Nian Ni Serge Kokot State Key Laboratory of Food Science and Technology Nanchang University Nanchang 330047 China Department of Chemistry Nanchang University Nanchang 330031 China Chemistry Faculty of Science and Technology Queensland University of Technology Brisbane 4001 Australia

The voltammetric behaviour of three 5-nitroimidazoles,metronidazole,tinidazole and ornidazole,was investigated,and a method was developed for the simultaneous determination of these compounds,based on their reduction at a hanging mercury drop electrode（HMDE） in pH 8.95 buffer with differential pulse voltammetric（DPV） approach.Well defined voltammetric waves with peak potentials of -692,-640 and -652 mV were observed for these compounds,respectively.It is difficult to determine them individually from their mixtures without preseparation,for their voltammetric peaks overlapped seriously,so the chemometrics were used to resolve the overlapped voltammogram and quantify the mixtures.The proposed method was successfully applied to the determination of three 5-nitroimidazoles in milk and honey samples.

关键词： Nitroimidazoles Metronidazole Tinidazole Ornidazole Chemometrics differential pulse voltammetry

4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

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Rare Metals 2003年第4期22卷 250-253页

作者： YANGSheng LUXiaoquan XUEZhonghua FENGXiaoqiang WANGXiaofeng DepartmentofChemistry TianshuiTeacherCollegeTianshui741001China InstituteofChemistry NorthwestNormalUniversityLanzhou730070China

A differential pulse voltammetric method was developed for the sensitive andselective determination of Cu(II) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modifiedcarbon paste electrode in 0.05 mol/L KHC_8H_4O_4 solution (pH = 4.02). The oxidation peak of Cu(II)was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direction. The analysisprocedure consisted of an open circuit accumulation step in stirred sample solution. It was followedby medium exchange to a clean solution and subsequently an anodic potential scan was affected toobtain the voltammetric peak. The current was proportional to the concentration of the Cu(II) ion ina range of 1 X 10^(-7) -1 X 10^(-4) mol/L for 6 min accumulation; the most of metal ions did notinterfere with the determination. The developed method was applied to Cu (II) determination incoal-ash sample, the results agreed with that of atomic adsorption spectroscopy (AAS).

关键词： analysis chemistry 4-Methoxy-2,6-bis (3,5-dimethylpyrazoyl)-1,3,5-triazine differential pulse voltammetry copper (II)

differential pulse Voltammetric Simultaneous Determination of Paracetamol and Omnipaque on Boron Doped Diamond Electrode: Application to Natural Tomato, Carrot, Cucumber Juices and Wastewater

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美国分析化学(英文) 2023年第10期14卷 434-450页

作者： Koffi Konan Martin Sadia Sahi Placide Kouadio Brou Albert Gnamba Corneil Quand-Même Fofié Thiery Auguste Appia Koffi Konan Sylvestre Lassiné Ouattara UFR Environnement Université Jean Lorougnon Guédé Daloa C&ocircte d’Ivoire UFR Sciences et Technologies Université Alassane Ouattara Bouaké C&ocircte d’Ivoire Laboratoire de constitution et de réaction de la matière UFR SSMT Université Félix Houphouet Boiguy Abidjan C&ocircte d’Ivoire

This article describes the use of a boron-doped diamond electrode (BDDE) as an electrochemical sensor for the simultaneous determination of omnipaque (OMP) and paracetamol (PCM) in perchloric acid medium (HClO4 0.1 M) and in complex matrices such as tomato, carrot and cucumber juices and waste water from the Treichville University Hospital. Voltammetric studies allowed us to have well-defined oxidation peaks at distinct potentials of OMP (E = 0.5 V/SCE) and PCM (E = 0.7 V/SCE). Under optimized conditions, well-defined quantities of OMP and PCM, introduced simultaneously by metered additions, gave linear responses in concentration ranges of 259.8 - 467.2 μM for OMP and 58.73 - 116.3 μM PCM. The detection limits obtained are 7.23 μΜ and 3.6 μΜ respectively for OMP and PCM with recovery rates between 85.8% ± 0.1% and 92.6% ± 0.1% for OMP and between 99.9% ± 0.1% and 101.2% ± 0.4% for the PCM. This technique has been successfully used to simultaneously detect these pharmaceuticals in these complex environments. It allows recovery of OMP and PCM respectively up to 97.5% ± 0.0% and 91.6% ± 0.3% in tomato juice;100.0% ± 0.0% and 95.2% ± 0.2% in carrot juice;101.4% ± 0.1% and 97.3% ± 0.3% in cucumber juice;100.1% ± 0.9% and 100.9% ± 0.1% in wastewater. The relevance of this technique for the simultaneous detection of OMP and PCM in tomato, carrot, cucumber juices and in waste water can be studied in the context of the contamination of certain fruits and vegetables by the substances organic pharmaceuticals released into the environment without prior treatment.

关键词： Omnipaque Paracétamol differential pulse voltammetry Boron Doped Diamond Electrode

Indirect differential pulse Voltammetric Determination of Aluminum by a Pyrocatechol Violet-Modified Electrode

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Chinese Chemical Letters 1999年第3期10卷 247-250页

作者： Shu Ping BI Gang CHEN(Department of Chemistry. Naming University, Naming 210093) Department of Chemistry Nanjing University Nanjing 210093 China

A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al and the peak potentials remain the same. The decreasing of Delta i(p) is linear with Al concentration in the range of 1 x 10(-8) similar to 1 x 10(-7) mol/L. The detection limit is 5 x 10(-9) mol/L and the relative standard deviation for 4 x 10(-8) mol/L Al is 2.9% (n=8). No serious interference was found. The determination of Al in water samples is reported.

关键词： pyrocatechol violet (PCV) aluminum chemically modified electrode differential pulse voltammetry indirect determination drinking water

Electrochemical Study and Application on Shikonin at Poly（diallyldimethylammonium chloride） Functionalized Graphene Sheets Modified Glass Carbon Electrode

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Chemical Research in Chinese Universities 2013年第4期29卷 798-805页

作者： AN Jing LI Ji-ping CHEN Wen-xia YANG Chun-xia HU Fang-di WANG Chun-ming School of Pharmacy Hospital of Lanzhou University College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P. R. China

The electrochemical behaviors of shikonin at a poly（diallyldimethylammonium chloride） functionalized graphene sheets modified glass carbon electrode（PDDA-GS/GCE） have been investigated. Shikonin could exhibit a pair of well-defined redox peaks at the PDDA-GS/GCE located at 0.681 V（Epa） and 0.662 V（Epc）[vs. saturated calo- mel electrode（SCE）] in 0.1 mol/L phosphate buffer solution（pH=2.0） with a peak-to-peak separation of about 20 mV, revealing a fast electron-transfer process. Moreover, the current response was remarkably increased at PDDA- GS/GCE compared with that at the bare GCE. The electrochemical behaviors of shikonin at the modified electrode were investigated. And the results indicate that the reaction involves the transfer of two electrons, accompanied by two protons and the electrochemical process is a diffusional-controlled electrode process. The electrochemical para- meters of shikonin at the modified electrode, the electron-transfer coefficient（a）, the electron-transfer number（n） and the electrode reaction rate constant（ks） were calculated to be as 0.53, 2.18 and 3.6 s^-1, respectively. Under the optimal conditions, the peak current of differential pulse voltammetry（DPV） increased linearly with the shikonin concentra- tion in a range from 9A72×10^-8 mol/L to 3,789×10^-6 mol/L with a detection limit of 3,157× 10^-8 mol/L. The linear regression equation was Ip=O.7366c＋0.7855（R=0.9978; lp： 10-7 A, c： 10-8 mol/L）. In addition, the modified glass carbon electrode also exhibited good stability, selectivity and acceptable reproducibility that could be used for the sensitive, simple and rapid determination of shikonin in real samples. Therefore, the present work offers a new way to broaden the analytical application of graphene in pharmaceutical analysis.

关键词： Shikonin Poly（diallyldimethylammonium chloride） functionalized graphene sheets modified glass carbon electrode（PDDA-GS/GCE） Cyclic voltammetry differential pulse voltammetry Electrochemical sensor

Fabrication of a Sensitive Electrochemical Biosensor for Detection of DNA Hybridization Based on Gold Nanoparti- cles/CuO Nanospindles Modified Glassy Carbon Electrode

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Chinese Journal of Chemistry 2012年第1期30卷 167-172页

作者：张玉忠王明珠黄蕾 College of Chemistry and Materials Science Anhui Key Laboratory of Chem-BiosensingAnhui Normal UniversityWuhuAnhui 241000China

In this work, a sensitive electrochemical DNA biosensor for the detection of sequence-specific target DNA was reported. Firstly, CuO nanospindles （CuO NS） were immobilized on the surface of a glassy carbon electrode （GCE）. Subsequently, gold nanoparticles （Au NPs） were introduced to the surface of CuO NS by the electrochemical deposition mode. Probe DNA with SH （HS-DNA） at the 5＇-phosphate end was covalently immobilized on the surface of the Au NPs through Au-S bond. Scanning electron microscopy （SEM） was used to elucidate the morphology of the assembled film, and electrochemical impedance spectroscopy technique （EIS） was used to investigate the DNA sensor assembly process. Hybridization detection of DNA was performed with differential pulse voltammetry （DPV） and the methylene blue （MB） was hybridization indicator. Under the optimal conditions, the decline of reduction peak current of MB （A/） was linear with the logarithm of the concentration of complementary DNA from 1.0 X 10-13 to 1.0× 10-6 mol·L l with a detection limit of 3.5 × 10 14 mol·L -1 （S/N=3）. In addition, this DNA biosensor has good selectivity, and even can distinguish single-mismatched target DNA.

关键词： DNA biosensors gold nanoparticles CuO nanospindles differential pulse voltammetry

Simultaneous Voltammetric Determination of Cd^(2+), Pb^(2+), and Hg^(2+) Ions Using Aminosepiolite-Coated Glassy Carbon Electrode: Optimization of Detection Parameters via Response Surface Methodology

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Journal of Analysis and Testing 2019年第4期3卷 295-305页

作者： Ervice Ymélé Sherman Lesly Zambou Jiokeng Divine Bup Nde Théophile Kamgaing Ignas Kenfack Tonlé Electrochemistry and Chemistry of Materials Department of ChemistryFaculty of ScienceUniversity of DschangP.O.Box 67DschangCameroon Higher Institute of the Sahel University of MarouaP.O.Box 46MarouaCameroon

Adsorptive stripping voltammetry using a glassy carbon electrode modified by a film of aminosepiolite was utilized for simultaneous pre-concentration and trace detection of cadmium,lead,and mercury ions in aqueous solution.The modified sepiolite exploited as electrode material was obtained by grafting on its surface of[(3-(2-aminoethylamino)propyl)]trimethoxysilane(AEPTMS).The results demonstrated that the amine groups on sepiolite efficiently affected the voltammetric detection of heavy metals.The full factorial design matrix and response surface methodology were applied in designing experiments,to determine the optimal conditions and to evaluate their mutual interactions.The high values of adjusted R2 obtained of the fitted model show that the experiments data were well explained by the model,which then allowed to acquire optimum parameters for the electroanalysis and detection of the analytes by differential pulse voltammetry.At pH 6.5 of accumulating medium,with an electrolysis potential of-0.9 V and in the concentration range of 10^(−8) M to 10^(−9) M,calibration plots were obtained.The limits of detection(3Sd/m)were 8.689×10^(−10) M,8.197×10^(−10) M,and 8.099×10^(−10) M,respectively,for Cd^(2+),Pb^(2+),and Hg^(2+)ions.The interference effect of several cations and anions on the response of the analytes was also evaluated,and finally,the sensor was applied to the simultaneous detection of metal ions in tap water with satisfactory recovery rates.

关键词： Aminosepiolite Surface response methodology Factorial design differential pulse voltammetry Heavy metals

Electrochemical Determination of Epinephrine with a Pyrolytic Graphite Electrode in the Presence of Ascorbic Acid and Dopamine

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Chinese Chemical Letters 2006年第5期17卷 657-660页

作者： Xiu Hui LIU Yan ZHANG Guo Fang ZUO Xiao Quan LU College of Chemistry ＆ Chemical Engineering Northwest Normal University Lanzhou 730070

A method for determination of epinephrine（EP） in the presence of ascorbic acid （AA） and dopamine （DA） with bare pyrolytic graphite electrodes has been described for the first time. In pH 7.0 phosphate buffer solution, the linear relationship was observed between the reduction peak current of EP and its concentration over the range from 1×10^-4 to 5×10^-7 mol/L, the related coefficient is 0.9992 （N=8）.

关键词： differential pulse voltammetry epinephrine ascorbic acid dopamine pyrolytic graphite electrodes

Direct and Simultaneous Determination of Phenol, Hydroquinone and Nitrophenol at Boron-Doped Diamond Film Electrode

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Chinese Journal of Chemistry 2007年第10期25卷 1445-1450页

作者：赵国华唐轶婷刘梅川雷燕竹肖小娥 Department of Chemistry Tongji University Shanghai 200092 China

The electrochemical characteristics of multi-component phenolic pollutants, such as phenol （Ph）, hydroquinone （HQ） and 4-nitrophenol （4-NP）, were investigated on boron-doped diamond （BDD） film electrode by differential pulse voltammetry （DPV） technique. A simple and feasible platform was accordingly established for the direct and simultaneous determination of these three phenolic pollutants. Results showed that, Ph, HQ and 4-NP gave obvious oxidation peaks on BDD electrode at the potential of 1.24, 0.76 and 1.52 V, respectively. Each of them displayed good linear relationship between their oxidation peak currents and their corresponding concentrations in a rather wide range coexisting with one or two of the other phenolic pollutants. The detection limits of Ph, HQ and 4-NP were estimated to be as low as 1.82×10^-6, 1.67×10^-6 and 1.44×10^-6 mol·L^-1, respectively. Therefore, a promising direct and simultaneous electrochemical determination method of multi-component phenolic pollutants in wastewater samples was constructed successfully on BDD electrode with advantages being rapid, simple, convenient, sensitive, in situ and inexpensive.

关键词： boron-doped diamond film electrode phenolic pollutant differential pulse voltammetry multi-component simultaneous determination