Estimation of serum nicotine by gas chromatography in smokers, passive smokers and never smokers.

To compare the serum nicotine levels in smokers, passive smokers and those with no exposure to cigarette smoke. The comparative study spanning two years was conducted in Ziauddin Medical University, Karachi, in collaboration with HEJ Research Institute of Chemical Sciences, University of Karachi from 2009 to 2011 involved 135 self-reported smokers, never smokers and passive smokers among whom serum nicotine was analysed using 17-A gas chromatograph with flame ionisation detector equipped with Supelco SPB-5 fused silica capillary column (45m x 0.53mm id and 0.5 um) attached with Class GC 10 Software. SPSS version 11.0 and Kruskal Wallis Test were used for statistical purposes. There were 43 (32%) smokers, 61 (45%) passive smokers and 31 (23%) never smokers in the study. Among the smokers 33 (77%) had serum nicotine greater than 10 ng/ml. The mean nicotine concentration of smokers was 55 +/- 6.1 ng/ml and mean rank was 98.3 which was significantly higher than passive and never smokers (p < 0.01). The method for the estimation of serum nicotine was fairly reliable. Serum nicotine was raised in smokers, and the effects of passive smoking was also seen through serum nicotine. However, more studies with increased sample size are required to establish it as an environmental tobacco smoke exposure marker.