Liquid chromatography with amperometric oxidative detection is proposed as a sensitive method for... more Liquid chromatography with amperometric oxidative detection is proposed as a sensitive method for the determination of aliphatic amines previously converted in thioureido derivatives by reaction with phenylisothiocyanate (PIT). The phenylthioureas of four model amines, methylamine (MA), propylamine (PA), n-butylamine (BA) and isobutylamine (IBA) have been synthesized and isolated. Their electrochemical behavior on a glassy carbon electrode has been explored by cyclic voltammetry. The thioureido derivatives can be oxidized through two one-electron steps at acidic pH values, presumably involving the intermediacy of proton transfers. A mechanistic pathway is also proposed on the basis of experimental data. Liquid chromatographic parameters as mobile phase composition and¯ow rate, temperature and working electrode potential have been optimized. The method permits the simultaneous determination of the phenylthioureas of the selected amines with detection limits in the lower mgL 71 range.
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Papers by Ankita Tiwari