- P-ISSN 1225-0163
- E-ISSN 2288-8985
The aim of this study is to assess the interference effect of other organic acids to the values of hippuric acid analysed by UV method. We calculated the interference effect of several metabolites of styrene and xylene, i.e., methylhippuric acid, phenylglyoxylic acid, and mandelic acid to hippuric acid, respectively. The result of interlaboratory quality control program of urinary hippuric acid showed that there was no significant difference between the results by UV and HPLC if there were no other organic acids in urine. However, 0.5-2.0 g/L methylhippuric acid showed positive interference of 64-82% to 0.33 g/L urinary hippuric acid while mandelic acid or phenylglyoxylic acid did not show this positive effect. We suggest that HPLC or GC method is more acceptable than UV method to analyse urinary hippuric acid for biological monitoring when the worker was exposed to mixture of toluene and xylene.