Hossein Tavalali; Abolfath Parhami; Mohammad Ali Karimi; Jamshid Askari
Abstract
In this study, a novel mixed ligand (Dithizone-Co(II)-Alizarin red S: DTZ-Co-ALR-) ensemble is designed and developed ultra-sensitive, and highly selective to UV-Vis absorption and for naked-eye detection of Arginine (Arg), and Glutathione (GSH). The out coming high sensitivity and selectivity for new ...
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In this study, a novel mixed ligand (Dithizone-Co(II)-Alizarin red S: DTZ-Co-ALR-) ensemble is designed and developed ultra-sensitive, and highly selective to UV-Vis absorption and for naked-eye detection of Arginine (Arg), and Glutathione (GSH). The out coming high sensitivity and selectivity for new receptor (DTZ-Co(II)-ALRs-Arg) was attained by adding Glutathione. The indicator is released due to its displacement from the mixed ligand (DTZ-Co-ALRs-Arg) by Glutathione and the change in absorbance may be due to the further complexation of GSH with the additional coordination sites present in the Arg bonded with the mixed ligand (DTZ-Co-ALRs). The label-free DTZ-Co-ALRs receptor provided sensitive and selective detection of L-Arginine, and Glutathione with detection limits of 0.03, and 0.009µmol L-1, respectively. The protocol especially offers high selectivity for the determination of Arg, and GSH among amino acids found in real samples. Moreover, the investigation of the logic behavior of the proposed DTZ-Co-ALRs receptor indicated its capability of functioning as an INHIBIT-type colorimetric chemosensor with the chemical inputs and UV-Vis absorbance signal as the output. This mixed ligand receptor could also behave as a molecular “keypad lock” with the correct sequential addition of Arg and GSH inputs.
Jahanbakhsh Raoof; Mohammad Ali Karimi; Leila Asadian-Zarrinabadi; Mohaddeseh Amiri-Aref
Volume 1, Issue 1 , March 2014, , Pages 12-19
Abstract
The electrochemical oxidation and determination of tryptophan (Trp) and glutathione (GSH) in the presence of catechol as a homogeneous redox in the aqueous medium were investigated at the surface of a carbon paste electrode modified with multi-walled carbon nanotube (MWCNT-CPE) using cyclic voltammetry ...
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The electrochemical oxidation and determination of tryptophan (Trp) and glutathione (GSH) in the presence of catechol as a homogeneous redox in the aqueous medium were investigated at the surface of a carbon paste electrode modified with multi-walled carbon nanotube (MWCNT-CPE) using cyclic voltammetry (CV), double step potential chronoamperometry and differential pulse voltammetry (DPV) techniques. The results of differential pulse voltammetry showed two well-resolved anodic peaks for glutathione and tryptophan, which leads to voltammetric determination of each of them. The results shows the electrooxidation peak currents of GSH and Trp is linear in the concentration range of 2×10-6 M-5×10-5 M and 4×10-6 M-6×10-5 M, respectively. The kinetic parameters such as: the chemical reaction rate constant (kh) and transfer coefficient (α) were calculated 2.01×102 cm3 mol-1 s-1 and 0.31, respectively. Also, the apparent diffusion coefficient, Dapp, for GSH was found to be 1.95×10-6 cm2 s-1 in aqueous buffered solution. The proposed method was successfully applied for determination of glutathione and tryptophan in real sample using standard addition method.
