Determination of Methionine in Medicines by Stripping Voltammetry

Resumo

A method is proposed for the determination of methionine by stripping voltammetry on a carbon-containing electrode modified by vitamin B₁₂. The procedure is based on the reaction of methionine reduction to homocysteine. The preparation of the electrode consists in the formation of a vitamin B₁₂ film on the surface of a carbon-containing electrode modified with carbon nanotubes by cyclic voltammetry with a potential sweep from –1.4 to +1 V. The conditions of analysis are optimized: accumulation potential, accumulation time, and sweep rate. The limit of detection for methionine is 1 × 10^–7 M.