A selective and sensitive LC/MS/MS assay was developed for the quantification of d2-nicotine and d2-cotinine in plasma of current and past smokers administered d2-nicotine. After solid phase extraction and liquid-liquid extraction, HPLC separation was achieved on a capillary hydrophilic interaction chromatography phase column. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated for d2-nicotine (0.03-6.0 ng/ml plasma) and d2-cotinine (0.15-25 ng/ml plasma). The lower limits of quantitation were 0.15 ng/ml and 0.25 ng/ml for d2-nicotine and d2-cotinine, respectively. The coefficient of variation was 3.7% for d2-nicotine and 2.5% for d2-cotinine. The method was applied to two ongoing studies of d2-nicotine metabolism in prior and current smokers. Preliminary analysis of a subset of subjects from these studies detected a significantly lower rate of nicotine conversion to cotinine by past smokers compared to current smokers.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences|
|State||Published - Sep 15 2007|
- Nicotine metabolism