Simultaneous determination of total homocysteine, cysteine and methionine in hypothyroid patients’ plasma by liquid chromatography using platinum/poly(methyl violet) modified electrode

• Published in: Analytica chimica acta 2005-07, Vol.545 (2), p.182-188
• Main Authors: Xu, Haihong, Zhang, Wen, Zhu, Wei, Wang, Dan, Ye, Jun, Yamamoto, Katsunobu, Jin, Litong
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Cysteine; Electrochemical methods; Exact sciences and technology; Homocysteine; Hypothyroid; Methionine; Other chromatographic methods; Pt particles/poly(methyl violet)
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2005.04.089

The fabrication and application of a novel electrochemical detection (ED) system with the platinum/poly(methyl violet) (Pt/MV) chemically modified electrode (CME) for high performance liquid chromatography (HPLC) were described. The Pt particles deposited on the poly-MV film were characterized by atomic force microscope (AFM). It was found that the Pt/MV CME exhibited efficiently electrocatalytic effect on the current responses of cysteine (Cys), homocysteine (Hcy) and methionine (Met) with relatively high sensitivity, stability and long-life of activity. In HPLC-ED, these three amino acids had good and stable current responses at the CME and their linear ranges were over three orders of magnitude ( R ≥ 0.9996) with the detection limits being 7.5 × 10 −8 mol L −1 for Cys, 1.0 × 10 −7 mol L −1 for Hcy, 5.0 × 10 −7 mol L −1 for Met. The application of this method coupled with microdialysis sampling for the determination of Cys, Hcy and Met in plasma from patients with hypothyroidism was satisfactory.