engleski

Comparison of headspace solid phase microextraction and liquid-liquid extraction for determining nicotine and cotinine in children's urine by gas chromatography/mass spectrometry

Environmental tobacco smoke (ETS) is a widespread pollutant with adverse health effects on nonsmokers. Nicotine and its main metabolite cotinine are commonly used as biomarkers of ETS exposure. Cotinine is mostly determined in urine, and appears to be the biomarker of choice for ETS exposure. Although exposure to ETS often involves determining nicotine and cotinine in urine, there are no data on the comparison of liquid-liquid extraction (LLE) and headspace solid phase microextraction (HS-SPME) as the extraction techniques for assessing the exposure to ETS. The aim of this study was to compare these two procedures used to extract nicotine and cotinine from nonsmokers’ urine and use selected procedure, together with gas chromatography/mass spectrometry (GC/MS) to quantify urinary nicotine and cotinine. Both methods showed linearity in the range 1 μg L-1 to 200 μg L-1, good accuracy (>90 %) and precision (RSD≤8.5 %), and low detection limits (0.15 μg L-1 to 0.25 μg L-1). In comparison with LLE-GC/MS, HS-SPME-GC/MS was simpler and faster and thus applied for the quantitative analysis of nicotine and cotinine in urine samples collected from 157 children. Children exposed to environmental tobacco smoke (n=81) had signifi cantly higher levels of nicotine (p<10-10) and cotinine (p<10-16) in urine than nonexposed children (n=76). No need for solvent use and sample preparation, high sensitivity and rapidity make the HS-SPME-GC/MS method more convenient for determining nicotine and cotinine in nonsmokers’ urine.

biomarkers of exposure; comparison of the extraction procedures; environmental tobacco smoke

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