engleski

Environmental exposure assessment to aromatic hydrocarbons by determination of benzene, toluene, ethylbenzene, and isomeric xylenes in urine

The objective of the study was to establish baseline concentration data for benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in the urine of the general population of Zagreb and to evaluate the effect of cigarette smoking. A method for determination of BTEX in urine is described. Determination is performed by dynamic headspace (purge and trap) gas chromatography with photoionization detection. The features of the method (detection limits of 9-27 ng/L, relative standard deviations of 0.2-10 %, accuracy of 80-100 %, removal of interference of many compounds present in urine, sharp chromatographic peaks because of cryogenic refocusing and no sample preparation) make it convenient for biological monitoring of exposure to low levels of BTEX. The method was applied for the quantitative analysis of BTEX in urine samples collected from 36 nonsmokers and 36 smokers. All urine samples had measurable BTEX concentrations but ethylbenzene in 13 and o-xylene in 15 samples of nonsmokers. A significant statistical difference (p<10-6) was found between urine concentrations of BTEX in smokers and nonsmokers. BTEX significantly intercorrelated, which can be expected because of their common origin from vehicle exhausts and smoking habit. Despite the relatively low number of subjects it was possible to present reference values of BTEX in urine as biomarkers of environmental exposure. The results show that smoking significantly contributes to the concentration of BTEX.

Benzene; toluene; ethylbenzene; isomeric xylenes; urine; exposure. dynamic headspace

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