title: Analysis of N-nitrosamines and other nitro(so) compounds in water by high-performance liquid chromatography with post-column UV photolysis/Griess reaction.
abstract: Despite their potential carcinogenicity and probable formation during water disinfection processes, little is known about the occurrence of other nitro(so) compounds than a few specific N-nitroso compounds such as N-nitrosodimethylamine (NDMA). An analytical method was developed to monitor various nitro(so) compounds including N-nitrosamines based on the Griess colorimetric determination of nitrite generated by UV-254 nm photolysis of nitro(so) compounds after separation by HPLC (HPLC-Post Column UV photolysis/Griess reaction (HPLC-PCUV)). To differentiate N-nitro(so) compounds (i.e. UV-labile) from other nitro(so) and N-containing compounds (i.e. UV-resistant), a pre-treatment was established by photolyzing solid-phase extracted samples at 254 nm (1000 mJ/cm(2)) and thus removing N-nitro(so) compounds selectively. Considering a 1000-fold concentration factor and extraction efficiencies (57-83%) during solid phase extraction, the method detection limits ranged from 4 to 28 ng/L for dimethylnitramine and eight N-nitrosamines (EPA 8270 nine nitrosamines mixture except for N-nitrosodiphenylamine). For four pool waters, the UV-resistant groups accounted for more than 78% of the estimated total concentration of nitro(so) and other N-containing compounds (6.1-48.6 nM). Only one unknown UV-labile compound was detected in one pool water (2.0-7.9 nM). NDMA was most frequently detected and N-nitrosodipropylamine (NDPA) and N-nitrosodibutylamine (NDBA) were additionally detected in one pool water. Chloramination of a secondary wastewater effluent with NDMA (0.2 nM) and UV-resistant compounds (7.9 nM) from a pilot-scale municipal wastewater treatment plant led to a significant formation of not only unidentified UV-resistant compounds (67.8 nM) and UV-labile compounds (14.6 nM), but also identified nitrosamines such as NDMA (4.3 nM), N-nitrosopiperidine (1.8 nM), NDPA (0.5 nM), and NDBA (0.5 nM). Overall, the novel HPLC-PCUV system is a powerful screening tool for the detection of (un)known N-nitro(so) as well as other nitro(so) and UV-induced nitrite-producing compounds.
authors.affiliation: School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Minju
authors.initials: M
authors.lastname: Lee
authors.forename: Yunho
authors.initials: Y
authors.lastname: Lee
authors.forename: Fabian
authors.initials: F
authors.lastname: Soltermann
authors.forename: Urs
authors.initials: U
authors.lastname: von Gunten
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004128:Dimethylnitrosamine / Q000032:analysis; D004867:Equipment Design; D054879:Halogenation; D057230:Limit of Detection; D009602:Nitrosamines / Q000032:analysis*; D010782:Photolysis; D052616:Solid Phase Extraction; D013551:Swimming Pools; D014466:Ultraviolet Rays; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D004128:Dimethylnitrosamine; D009602:Nitrosamines; D062065:Wastewater; D014874:Water Pollutants, Chemical; C002743:N-nitrosopiperidine; C012279:dibutylnitrosamine; C023649:N-nitrosodiphenylamine
keywords: Griess reaction; HPLC post-column reaction; N-nitrosamines; N-nitrosodimethylamine (NDMA); Nitro(so) compounds; Swimming pool water; Wastewater