Simultaneous determination of p-aminobenzoic acid and its metabolites in urine by high performance liquid chromatography.

We developed a new HPLC method for the determination of p-aminobenzoic acid (PABA) and its metabolites (p-aminohippuric acid, N-acetyl-p-aminohippuric acid, N-acetyl-p-aminobenzoic acid) in urine. As the internal standard m-hydroxybenzoic acid was used. In the isocratic elution the mobile phase consisted of methanol and 0.02 M ammonium acetate (20:80 v/v, pH 4.0). The separation was carried out on the C18, reversed-phase column, particle size 5 microns. The separated components were detected at 280 nm. The method can be used in the assessment of the response of pancrease (secretion of digestive enzymes) to soya feeding as well as in the diagnosis of the exocrine pancreatic diseases of animals.