Fast Screening for Tobacco-Specific N-nitrosamines by CZE Using Dynamically Coated Capillaries

In this paper, we propose a rapid capillary zone electrophoretic method with dynamically coated capillaries for separation of and screening for six tobacco-specific nitrosamines, a group of strong carcinogens found only in tobacco products. Dynamic coating of the capillary surface with a polycation coating (CElixir Reagent A) followed by a polyanion coating (CElixir Reagent B; pH 2.5) was accomplished by use of a commercially available reagent kit. With this method, six tobacco-specific nitrosamines: N′-nitrosonornicotine, N′-nitrosoanatabine, N′-nitrosoanabasine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, and 4-(methylnitroamino)-4-(3-pyridyl)-1-butanol were simultaneously separated and determined within 3 min, with a satisfactory detection limit of 1.0 μg mL−1 for all the tobacco-specific nitrosamines at S/N = 3, and a linear relationship between UV absorbance and analyte concentration (R 2 > 0.98). The repeatability of the method ranged from 0.24 to 0.73% (RSD, n = 5) for migration time and 0.25–1.54% (RSD, n = 5) for peak area, demonstrating that this capillary electrophoretic method is better than conventional capillary zone electrophoresis.