Determination of thiocompounds by liquid chromatography with amperometric detection at a Nafion indium hexacyanoferrate film modified electrode

作者：Zhang S; Sun WL; Zhang W; Qi WY; Jin LT^*; Yamamoto K; Tao SG; Jin JY

来源：Analytica Chimica Acta, 1999, 386(1-2): 21-30.

DOI：10.1016/S0003-2670(98)00799-5

• liquid chromatography
• electrochemical detection
• indium hexacyanoferrate
• chemically modified electrode

Polynuclear indium(III) hexacyanoferrate(II, III) thin films are electrodeposited on a glassy carbon (GC) electrode through potential cycling between 1.1 and 0.0 V vs. SCE in a fresh modification solution containing potassium, indium(III) and hexacyanoferrate(III) ions. During the negative scans, the cationic In3+ species interact with the simultaneously generated anionic Fe(CN)(6)(4-) to yield a sparingly soluble mixed-valent coating on the electrode. Coated with Nafion film, the chemically modified electrode (CME) shows a better stability. The CME shows a single set of reversible, well-defined peaksc significantly separated from the solution responses. The apparent surface coverage is found to be 6.3 x 10(-9) mol/cm(2). This CME exhibits an efficient catalytic activity towards the rapid oxidation of thiocompounds in cyclic voltammetry, Cysteine (Cys), glutathione (GSH), 6-thiopurine (6-TP) and methimazole (MMI) have good and stable current responses at the CME in liquid chromatography with electrochemical detection (LC-ECD). The linear ranges are over three orders of magnitude and the detection limits are 1.6 pmol for Cys, 20 pmol for GSH, 20 pmol for 6-TP and 1.6 pmol for MMI. The method has been successfully applied to assess the purity of methimazole, the contents of cysteine in human urine and other thiocompounds in artificial urines.

• 出版日期1999-4-9
• 单位华东师范大学