Analysis of N'-nitrosonornicotine and its metabolites in rabbit blood with liquid chromatography/tandem mass spectrometric method.

N'-nitrosonornicotine (NNN) is a strong carcinogen. The metabolic study of NNN in vivo will help us to further understand it, however, trace detection in complex matrices requires highly sensitive detection methods. After the chromatographic conditions and mass spectrometric conditions had been optimized and confirmed, a method for determining NNN and its metabolites in rabbit blood by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) was established. The results showed that precisions (R.S.Ds) were between 0.5% and 8.62%, the recoveries ranged from 80% to 111%. Linearity was observed for all compounds with detection limits ranging from 0.039 ng mL⁻¹ to 0.217 ng mL⁻¹. Metabolic curves and pharmacokinetic parameters were obtained for NNN and its metabolites. The elimination half-life of NNN was 30 min and the main metabolite of NNN was 4-hydroxy-4-(3-pyridyl)-butyric acid (hydroxy acid) and the major metabolic pathway was 5'-hydroxylation and subsequent secondary metabolite formation.