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چكيده انگليسي :

Modified Vinylferrocene Carbon Nanotubes Paste Electrode as an Electrochemical Sensor for Determination of Glutathione Captopril Maliheh Monsef m monsef@ch iut ac ir February 6 2012 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiAli A Ensafi Email Ensafi@cc iut ac irAbstract Glutathione glutamylcysteinylglycine is atripeptidethiol present in all eukaryotic and probiotic 1cells GSH is widely distributed biological cells and is involved in many important physiologicalphenomena including protecting cells against oxidative damage influencing enzyme activity and thesynthesis of proteins and in the defense mechanism against abiotic stress Captopril CAP 2S 1 2S 2 methyl 3 sulfanylpropanoyl pyrrolidine 2 carboxylic acid an activeinhibitor of the angiotensin converting enzyme ACE has been used for the treatment of hypertensivediseases and moderate heart failure as such or in combination with other drugs Vinylferrocene modified carbon nanotubes paste electrode VFMCNTPE was prepared and used as asensitive and selective electrochemical method was developed for determination of Glutathione GSH andCaptopril Cyclic voltammetry linear sweep voltammetry chronoamperometry and electrochemicalimpedance spectroscopy were used as diagnostic and measurement techniques Cyclic voltammetricinvestigation showed that GSH and Captopril didn t show any distinguishable anodic peak in the scaningregion potential 0 1 0V versus Ag AgCl electrode Some of parameter such as pH for the determination ofGSH Captopril were optimized pH 8 and 1 concentration Vinylferrocene percent for both of them wereselected Typical SEM images of different electrodes showed After multiwall carbon nanotubes MWCNTs added tothe carbon paste it can be seen that MWCNTs were distributed on the electrode with special three dimensional structure indicating that the MWCNTs were successfully modified on VFMCNTPE Inaddition it can be clearly seen that the mediator dispersed homogeneously in modified electrode Under the optimized conditions the electrocatalytic oxidation peak current of GSH showed two lineardynamic ranges with a detection limit of 0 09 mol L 1 GSH The linear calibration ranges were obtainedbetween 0 2 4 0 Bmol L 1 and 4 0 250 0 Bmol L 1 GSH using square wave voltammetry SWV The relativestandard deviation RSD for 5 replicated analysis of 10BM is 1 1 The chronoamperometry was used todetermine the catalytic rate constant and diffusion coefficient for the catalytic reaction of vinylferrocene withGSH Interference study indicated that there is no interference except ascorbic acid Finally the proposedsensor was also examined as a selective simple and precise electrochemical sensor for the determination ofGSH in real samples such as urine and hemolysed erythrocyte On the second work the calibration curve for Captopril was linear in the concentration range from 0 2 to 400BM and detection limit of 0 08 BM under the best experimental conditions selected The relative standarddeviation RSD for 6 replicated analysis of 100 BM and 300 BM are 1 9 2 1 respectivelyelectrochemical impedance spectroscopy was used to study the charge transfer properties at the electrode solution interface Also the values of the catalytic rate constant k and diffusion coefficient D forCaptopril were calculated Although ascorbic acid shows interference its interference can be minimized ifnecessary by using the ascorbic oxidase enzyme Finally the sensor was examined as a selective simple and precise new electrochemical sensor for the determination of captopril in real samples such as drug andurine with satisfactory results Keywords Voltammetry Multiwall carbon nanotubes paste electrode Vinylferrocene ElectrochemicalImpedance Spectroscopy Glutathione determination Captopril determination

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ساخت الكترود خمير كربن اصلاح شده با نانو لوله هاي كربن وينيل فروسن جهت اندازه گيري برخي از تركيبات و داروهاي بيولوژيكي به عنوان يك سنسور الكتروشيميايي

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