engleski

Determination of nicotine and cotinine in urine by headspace solid-phase microextraction gas chromatography with mass spectrometric detection

Environmental tobacco smoke (ETS) is widespread pollutant despite growing awareness of its adverse health effects on non-smokers. Nicotine and its main metabolite cotinine are widely used as biomarkers of ETS exposure and can be measured in blood [1], saliva [1, 2], urine [1-3], and hair [2]. Concentrations of biomarkers in biological fluids reflect recent exposure, while their concentrations in hair reflect longer-term exposure. Cotinine is mostly determined in urine, a biological medium easy to obtain. Because of the longer urinary half-life of cotinine compared with nicotine (20 versus 2 hours), cotinine in urine is currently considered to be the biomarker of choice for ETS exposure [4]. Many methods have been reported for the analysis of nicotine and cotinine in urine of nonsmokers such as gas chromatography using mass spectrometry (GC-MS) [1, 2] and nitrogen-phosphorus detector (NPD) [5, 6], high-performance liquid chromatography (HPLC) [3, 5], radioimmunoassay (RIA) [7], and enzyme linked immunosorbent assay (ELISA) [5, 8]. A simple and rapid method for determination of nicotine and cotinine in urine has been developed. The method is based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatographic determination and mass spectrometric detection. One mililitre of urine sample and 10 microlitres of diphenylamine as internal standard for nicotine and cotinine were added in the vial containing 1.3 g of potassium carbonate. The sealed vial was heated at 80 oC for 60 minutes. The SPME needle was passed through the septum and the extraction fibre was exposed to the headspace above the urine for 15 minutes. The needle was removed from the vial after retracting the fiber, and inserted into the injection port of GC-MS where analytes were desorbed at 280 oC for 10 minutes. The calibration curves were linear (r > 0.9998) over the concentration range tested (1-500 microgram/L), with detection limits of 1.1 microgram/L and 0.9 microgram/L for nicotine and cotinine, respectively. Intra-day precision of nicotine and cotinine determination (expressed as relative standard deviation) was < 9 %. The accuracy of the method ranged from 90 to 99 %. The method was applied for the quantitative analysis of nicotine and cotinine in urine samples collected from 30 nonsmokers, 15 without any ETS exposure (group I) and 15 who reported exposure to ETS (group II). There were statistically significant differences between groups I and II for nicotine (p<10^-4 ; ranges 2.1-28.0 and 10.1-499.7 microgram/L) and cotinine (p<10^-5 ; ranges <0.9-15.0 and 14.5-200.9 microgtam/L). Good sensitivity, short analysis time, small sample volume, no solvent use and sample preparation, make the method convenient for determination of nicotine and cotinine in nonsmokers&#8217; urine. [1] H.S. SHIN, J.G. Kim, Y.J. Shin, S.H. Jee, J. chromatogr. B 769(2002)177-183. [2] J.S. Torano, H.J.M. van Kan, Analyst 128(2003)838-843. [3] A. Thaqi, K. Franke, G. Merkel, H.E. Wichmann, J. Heinrich, Indoor Air 15(2005)302-310. [4] P.Dhar, J. Pharm. Biomed. Anal. 35(2004)155-168. [5] H.W. Kuo, J.S. Yang, M.C. Chiu, J. Chromatogr. B 768(2002)297-303. [6] R. Bono, M. Vincenti, T. Schiliro, D. Traversi, C. Pignata, E. Scursatone, G. Dotti, G. Gilli, J. Expo. Anal. Environ. Epidemiol. 15(2005)66-73. [7] S. de Weerd, C.M.G. Thomas, J.E.T.G. Kuster, R.J.L.M. Cikot, E.A.P. Steegers, Environ. Res. 90(2002)119-124. [8] W.K. Al-Delaimy, J. Crane, A. Woodward, J. Epidemiol. Community Health 56(2002)66-71.

cotinine; nicotine; nonsmokers; urine; HS-SPME; GC-MS

nije evidentirano