Determination of total pentachlorophenol in the urine of workers. A method incorporating hydrolysis, an internal standard and measurement by liquid chromatography.

Free pentachlorophenol (PCP) represents a small and variable fraction of total PCP excreted in the urine of exposed workers. A method incorporating hydrolysis is essential to be able to relate PCP excretion to absorbed dose. 3,5-Dichloro-2,4,6-tribromophenol (DTP) is added as an internal standard to a urine sample which is then acidified and steam-distilled. The distillate is made alkaline and extracted with methylene chloride to remove interferences. The distillate is then acidified and the phenols extracted into methylene chloride. The extract is evaporated, redissolved in acetonitrile and the PCP is measured using high pressure liquid chromatography (HPLC) using a 15 X 0.46 cm Spherisob-ODS 5 microns column with isocratic elution (H2O:CH3CN:CH3CO2H, 45:55:0.3 v/v). Detection is by fixed wavelength detector at 313 nm and calculation by the method of internal standardization. The biological threshold value used to trigger action to reduce exposure is 7 mg/l (corrected to a specific gravity of 1.024).

Simultaneous determination by gas chromatography of the major metabolites in urine of toluene, xylenes and styrene.

A gas chromatographic method has been developed to determine the following metabolites in urine simultaneously if necessary: hippuric acid from toluene or styrene; 3- and 4-methyl hippuric acids from xylenes; phenylglyoxylic acid and mandelic acid from styrene. Heptadecanoic acid is added to the urine as an internal standard and after ethyl acetate extraction from acidic solution, the trimethylsilyl (TMS) derivatives of the metabolites are formed and simultaneously analysed by gas chromatography on 3% OV-1 on 80/100 gas chrom Q (flame ionisation detector).