Determination of Vitamin B1 in Pharmaceutical Preparations by Flow-injection Analysis with Biamperometric Detection

A new electrochemical method for the on-line determination of vitamin B1 is presented. Based on dead-stop endpoint biamperometry by using two platinum foil electrodes with an applied potential difference of 150 mV, vitamin B1can be oxidized by hexacyanoferrate ( Ⅲ ) in a sodium hydroxide medium via a reversible indicating couple Fe( CN)64-/Fe(CN)63-. The cell current is linear with the concentration of vitamin B1 in the concentration range of 4.0×10-6-1.0 × 10-3 mol/L with a detection limit of 8.0×10-7 mol/L(0. 27 μg/mL). Most familiar excipients,ions and vitamins do not interfere with the determination of vitamin B1. The method displays the advantages of simplicity, high efficiency( 180 samples/h), and high selectivity, and is suitable for the determination of vitamin B1 in pharmaceutical preparations.