Abstract
Hippuric acid in the human urine was determined by high-performance liquid chromatography with a UV detector by use of stainless column (4.0 mm×0.15 m) packed with Nucleosil 5C18. Mobile phase was H2O-methanol (80 : 20), adjusted to pH 3.0 with H3PO4. The sample solution was extracted with ethyl acetate after adjusting to pH 1.0 with 6N HCl. Determination was carried out successfully by using vanillic acid as an internal standard and by maintaining the temperature at 40°. The recovery of hippuric acid from aqueous solution (0.5 mg/ml) was 96.0±1.5%. The contents of hippuric acid detected in samples from suspected persons of toluene inhalation were 4.83, 16.01, 2.48 and 6.41 mg/ml, respectively.
