A new method for the simultaneous determination of urinary NNAL and cotinine concentrations using HILIC-MS/MS coupled with PRiME HLB SPE

Urinary cotinine and NNAL are the biomarkers of tobacco smoke exposure and tobacco specific nitrosamines (TSNAs), respectively. A new method for the simultaneous analysis of them by hydrophilic interaction liquid chromatography tandem mass (HILIC-MS/MS) combined with PRiME HLB solid phase extraction (SPE) was developed. The sample matrix was removed effectively with PRiME HLB SPE and HILIC separation. The linearities were good in a range of 5.00-3.00 × 103 ng/L for NNAL and 0.200-4.00 × 102 μg/L for cotinine. The method detection limit of NNAL (0.0580 ng/L) was better than that in other literatures, and 0.0240 μg/L for cotinine. Recoveries were 91.6-110% and 88.7-113% with relative standard deviations of 3.78-9.12% and 0.120-1.15% for NNAL and cotinine, respectively. 29 urine samples were detected by the established method. The contents of NNAL and cotinine were 0.590-66.7 ng/g·Cr and 2.86-1.34 × 103 μg/g·Cr, respectively. Moreover, the results showed that urinary NNAL and cotinine were significantly positive correlation, even in passive smokers.