High performance liquid chromatographic determination of folic acid and its photodegradation products in the presence of riboflavin

Abstract

A high performance liquid chromatographic procedure was developed to determine folic acid and its photodegradation products, p-aminobenzoic acid, pterine-6-carboxylic acid, p- aminobenzoyl- l-glutamic acid, and pteroic acid in the presence of riboflavin. The method involves reversed phase, paired-ion chromatography on μ-BondaPak C 18 column using a UV detector (254 nm), and isocratic solvent system (at ambient temperature) comprising 0.017 M monobasic potassium phosphate, tetrabutyl ammonium hydroxide solution (20%, aqueous) and methanol (870:15:250, v/v). The range of quantitation for the individual compounds was found to be: p-aminobenzoic acid, 0.01–1.25 × 10 −5 M; pterine-6-carboxylic acid, 0.01–2.0 × 10 −5 M; p- aminobenzoyl- l-glutamic acid, 0.02–2.0 × 10 −5 M; pteroic acid, 0.02–2.5 × 10 −5 M; folic acid, 1.0–5.0 × 10 −5 M; riboflavin, 1.0–5.0 × 10 −5 M. Linear regression analysis of the data demonstrates adequate performance of the method in terms of accuracy and precision (R.S.D. 3%). The method is specific, rapid and convenient and has been applied to photodegradation studies of folic acid in the presence and absence of riboflavin.