New voltammetric procedure for determination of thiamine in commercially available juices and pharmaceutical formulation using a lead film electrode

A simple, reliable and reproducible method, based on adsorptive stripping voltammetry (AdSV), for determination of vitamin B-1 (thiamine) in pharmaceutical preparation and food is described in this paper. The in situ plated lead film electrode was used as a working electrode. The lead film was formed and thiamine was accumulated at -1.25 V (vs. Ag/AgCl) on a glassy carbon electrode. Then, the preconcentrated thiamine was reduced by scanning the potential of the electrode from -1.25 to -1.55 V using a square-wave technique. The linear range was from 0.0133 to 0.265 mg L-1 for vitamin B-1, with the regression coefficient of 0.999. The detection limit for vitamin B-1 was 0.0053 mg L-1 for the accumulation time 120 s. The method developed was applied to the determination of thiamine in certified reference material (BCR-485), pharmaceutical formulation and commercially available juices, and the assay results were satisfactory. (C) 2012 Elsevier Ltd. All rights reserved.