monitored for D-and D9-trans-3′-hydroxycotinine were m/z 193 → 80 and m/z 202 → 84, respectively. The limits of quantitation for D2-nicotine, D2-cotinine, D2 trans 3′-hydroxycotinine were 0.25, 0.25 and 0.6 ng/ml plasma. D2-nicotine, D2-cotinine, and D0-cotinine plasma concentrations were determined for all subjects at 30, 150 and 240 min, D2 trans 3′-hydroxycotinine in all subjects at 240 min, and D0 trans-3′-hydroxycotinine in all current smokers at 240 min.
