title: Separation of N-nitrosoamino acids by C18 reversed-phase ion-pair high-performance liquid chromatography and compatible detection by electrospray ionization mass spectrometry.
abstract: Four non-volatile N-nitrosoamino acids, namely N-nitrososarcosine, N-nitrosoproline, N-nitrosothiazolidine-4-carboxylic acid and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid were separated by C18 reversed-phase ion-pair high-performance liquid chromatography (HPLC) using 1.4 mM C16-cetyltrimethylammonium chloride in methanol-water-acetonitrile (60:35:5, v/v) as the mobile phase. The N-nitrosoamino acids were sensitively detected by negative electrospray ionization mass spectrometry (ESI-MS) in the form of the deprotonated carboxylate anion, [M-H]-. Compatibility problems associated with HPLC separation and ESI-MS detection, such as formation of solvent cluster ions and the effects of co-eluting anions of the ion-pairing reagent, were systematically investigated. The optimized experimental conditions for separation and detection of N-nitrosoamino acids were described.
authors.affiliation: Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Kowloon.
authors.forename: C F
authors.initials: CF
authors.lastname: Cheng
authors.forename: C W
authors.initials: CW
authors.lastname: Tsang
mesh_terms: D000838:Anions; D002712:Chlorides / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D013058:Mass Spectrometry; D009602:Nitrosamines / Q000032:analysis; D009603:Nitroso Compounds / Q000032:analysis*; D012997:Solvents / Q000737:chemistry; D013844:Thiazoles / Q000032:analysis; D053778:Thiazolidines
chemical_list: D000838:Anions; D002712:Chlorides; C041920:N-nitroso-2-methylthiazolidine-4-carboxylic acid; D009602:Nitrosamines; D009603:Nitroso Compounds; D012997:Solvents; D013844:Thiazoles; D053778:Thiazolidines; C040387:N-nitrosothiazolidine-4-carboxylic acid; C010259:nitrosoproline