%0 Journal Article %T Voltammetric Determination of Tryptophan Using a Carbon Paste Electrode Modified with Magnesium Core Shell Nanocomposite and Ionic Liquids %J Analytical and Bioanalytical Chemistry Research %I Iranian Chemical Society %Z 2383-093X %A Mohammadi, Sayed Zia %A Beitollahi, Hadi %A Hassanzadeh, Mohsen %D 2018 %\ 06/01/2018 %V 5 %N 1 %P 55-65 %! Voltammetric Determination of Tryptophan Using a Carbon Paste Electrode Modified with Magnesium Core Shell Nanocomposite and Ionic Liquids %K tryptophan %K Magnetic core-shell manganese ferrite nanoparticles %K Ionic Liquids %K Chemically modified electrodes %R 10.22036/abcr.2017.88326.1149 %X A novel carbon paste electrode modified with ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) and magnetic core-shell manganese ferrite nanoparticles (MCSILCPE) was fabricated. The electrochemical study of the modified electrode, as well as its efficiency for electro-oxidation of tryptophan, is described. Cyclic voltammetry (CV), choronoamperometry (CHA) and square wave voltammetry (SWV) were used to investigate oxidation of tryptophan in aqueous solution. The diffusion coefficient (D=3.53 ×10-6 cm2/s), was determined using electrochemical approaches. It has been found that under an optimum condition (pH 7.0), the oxidation of tryptophan at the surface of such an electrode occurs at a potential about 150 mV less positive than that of an unmodified carbon paste electrode. SWV exhibits a linear dynamic range from 5.0×10-6 to 4.0×10−4 M tryptophan. The morphology of the modified electrode was studied using SEM. The limit of detection was equal to 1.1×10-6 M. The electrode was also employed to determination of tryptophan in urine samples. %U https://www.analchemres.org/article_50854_1d19a500c075c0c5c9fb135907f04f7d.pdf