Determination of Folic Acid at a Bismuth Film Electrode by Adsorptive Stripping Voltammetry

Abstract

This article reports a new simple and sensitive method for the determination of folic acid by adsorptive stripping voltammetry. The method is based on the accumulation of folic acid at a bismuth film plated in situ on a glassy carbon substrate. In order to stabilize bismuth ions, sodium potassium tartrate was added to the supporting electrolyte. The bismuth film formation and folic acid accumulation conditions were optimized and measurements were carried without solution deaeration. The calibration graph was linear from 5 × 10−10 to 2 × 10−8 mole per liter with an accumulation time of 180 seconds with a limit of detection of 2 × 10−10 mole per liter. The relative standard deviation for 5 × 10−9 mole per liter of folic acid was 3.1 percent (n = 5). The method was successfully applied for determination of folic acid in pharmaceutical preparations.