Electrochemical behavior of isometamidium and its determination in milk at a SWCNT/AuNP-modified electrode

摘要

Isometamidium (ISM) residues in milk can cause health problems to human beings. This manuscript described for the first time an electrochemical method for ISM analysis in milk samples. The voltammetric behavior of ISM over an extended pH range using both cyclic voltammetry and differential pulse voltammetry at a glassy carbon electrode (GCE) was also studied. In order to improve the analytical performance, GC electrodes were modified with aniline and 1,4-phenylenediamine to form a stable layer, and then single-walled carbon nanotubes (SWCNT) were covalently bound to the GC electrodes. Gold nanoparticles (AuNP) were electrodeposited to the GC electrodes through the C-Au bonds to further promote the electrode conductivity. The modified SWCNT/AuNP-GCE electrochemical sensor (EC) was successfully applied to analyze isometamidium residues in milk. The linear range was from 10 mu g to 400 mu g/L with limit of detection at 3 mu g/L (S/N = 3). The recovery was between 79.4-94.7 % in spiked samples. The EC sensor method was also compared with a LC-MS/MS method, which proves its capability in commercial market surveillance.