Determination of free and total S-phenylmercapturic acid by HPLC/MS/MS in the biological monitoring of benzene exposure.

Urinary S-phenylmercapturic acid (SPMA) is a biomarker suggested by the American Conference of Governmental Industrial Hygienists (ACGIH) for assessing occupational exposure to benzene. A possible cause of the miscorrelation between environmental monitoring and biological monitoring for benzene exposure, which many authors complain about, is the existence of a urinary metabolite that turns into SPMA by acid hydrolysis. Forty urine samples were tested to determine which concentration value would correspond to the ACGIH Biological Exposure Index (BEI) of 25 microg g(-1) creatinine if exposure assessment was based on the determination of SPMA after quantitative hydrolysis of its precursor. An aliquot of each sample was hydrolysed with 9 M H2SO4, a second one was brought to pH 2 and a third one was used as it was (free SPMA). SPMA was determined by high-performance liquid chromatography/tandem mass spectrometric technique (HPLC/MS/MS) using an internal standard. The analytical method was validated in the range 0.5-50 microg 1(-1). The average SPMA in pH 2 samples is 45-60% of the total, while free SPMA varies from 1% to 66%. The hydrolysis of pre-SPMA reduces the likelihood of variability in the results by reducing pH differences in urine samples and increasing the amount of measured SPMA. The BEI limit value would be about 50 microg g(-1) creatinine.

Phenylmercury and its mobilization in the organism by a metal complex-forming substance: 2,3-dimercapto-1-propane sodium sulfonate.

Workers handling dressing machines for seed treatment with the product Agronal, containing a phenylmercury chloride fungicide, were exposed to high concentrations of phenylmercury dust in the working environment. Urine analyses for mercury result in concentration of up to 0.1 mg Hg/l of urine. After administration of a complex-forming substance-Unitol (2,3-dimercapto-1-propane sodium sulfonate)-a higher urinary excretion of mercury occurred. The amount of mercury excreted confirmed its deposit in the organism. It was speculated that subjective complaints by workers handling dressing machines could be caused by high exposure to phenylmercury. This suggestion cannot, however, be fully accepted because the complaints were not necessarily specific for mercury only, but could also have been caused by factors of nontoxic origin, such as stress at the workplace, discontent with work and environmental hygiene conditions, conflicts and alcoholism. Most probably, it was a case of interpotentiation of the effects of toxic and non-toxic nature.