A time-saving procedure for the determination of total trichloro-compounds in human urine samples

Green chemistry in urinalysis for trichloroethanol and trichloroacetic acid as markers of exposure to chlorinated hydrocarbon solvents

The aim of the present study was to develop a method of urinalysis for trichloroacetic acid (TCA) and trichloroethanol (TCE), and therefore total trichloro-compounds (TTC) as the sum, with least use of hazardous chemicals, being green in that sense. After acid hydrolysis followed by dilution with an ethanol (EtOH)-methanol (MeOH)-water mixture, capillary gas-choromatography with an electron-capture detector can quantify TCA and TCE in the diluted hydrolyzate. Comparison studies showed that the results were identical among three methods, i.e., 1. the method developed in the present study, 2. a head-space GC with acid hydrolysis of conjugated TCE and methyl-esterification of TCA, and 3. traditional colorimetry with Fujiwara reaction. When applied to exposure-excretion analysis, the three methods gave results reproducible to each other. Over-all evaluation therefore was such that the method developed in the present study is as equally reliable as previously developed methods. It should be further noted that the procedures are very simple, with minimum use of occupationally or environmentally hazardous chemicals. In case the determination of only TCA is requested, it is possible to skip the hydrolysis step so that the treatment prior to the GC analysis is even simpler, i.e., just a 60-fold dilution of the urine sample with the EtOH-MeOH-water mixture. It was also demonstrated that correction of urinary analyte levels for urine density in terms of creatinine or specific gravity did not improve the correlation with the intensity of TRI exposure.

Determination of metabolites (including thioethers) of mutagens and/or carcinogens as exposure indicators

Biological assessment of exposure to environmental hazards offers the potential for: (1) evaluation of exposure to prevent health impairment and (2) early detection of health effects. Two main methods of assessment can be used: (1) evaluation of the biological specimen for the exposed chemical or its metabolites and (2) measurement of the biological or clinical effects. There has been rapid improvement in the sensitivity of analytical techniques in the last decade and biological specimens of trace quantity can now be used for routine determinations. In this paper the current practice for monitoring populations exposed to benzene, styrene trichloroethylene, tetrachloroethylene and to some mutagens/ carcinogens are described. The practical concerns associated with routine urinary analyses, such as sample collection, sample preparation and interpretation of results are also discussed.