title: A rapid and reliable technique for N-nitrosodimethylamine analysis in reclaimed water by HPLC-photochemical reaction-chemiluminescence.
abstract: A fast and reliable analytical technique was evaluated and validated for determination of N-nitrosodimethylamine (NDMA) formation and rejection by reverse osmosis (RO) membranes in potable water reuse applications. The analytical instrument used in this study is high-performance liquid chromatography (HPLC), photochemical reaction (PR) and chemiluminescence (CL) - namely HPLC-PR-CL. Results reported here show that HPLC-PR-CL can be used to measure NDMA with a similar level of accuracy compared to conventional and more time-consuming techniques using gas chromatography and tandem mass spectrometry detection in combination with solid phase extraction. Among key residual chemicals (i.e. monochloramine, hydrogen peroxide and hypochlorite) in reclaimed wastewater, hypochlorite was the only constituent that interfered with the determination of NDMA by HPLC-PR-CL. However, hypochlorite interference was eliminated by adding ascorbic acid as a reducing agent. Direct injection of ultrafiltration (UF)-treated wastewater samples into HPLC-PR-CL also resulted in an underestimation of the NDMA concentration possibly due to interference by organic substances in the UF-treated wastewater. Accurate determination of NDMA concentrations in UF-treated wastewater was achieved by reducing the sample injection volume from 200 to 20 μL, though this increased the method detection limit from 0.2 to 2 ng/L. In contrast, no interference was observed with RO permeate. These results suggest that RO membranes could remove part of substances that interfere with the NDMA analysis by HPLC-PR-CL. In addition, RO treatment experiments demonstrated that HPLC-PR-CL was capable of evaluating near real-time variation in NDMA rejection by RO.
authors.affiliation: Water and Environmental Engineering, Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan. Electronic address: tfujioka@nagasaki-u.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujioka
authors.affiliation: Research Center for Environmental Quality Management, Kyoto University, Shiga 520-0811, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Research Center for Environmental Quality Management, Kyoto University, Shiga 520-0811, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil Mining and Environmental Engineering, The University of Wollongong, NSW 2522, Australia.
authors.forename: Long D
authors.initials: LD
authors.lastname: Nghiem
authors.affiliation: Orange County Water District, 18700 Ward Street, Fountain Valley, CA 92708, USA.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Ishida
authors.affiliation: Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kodamatani
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004128:Dimethylnitrosamine / Q000032:analysis* / Q000737:chemistry; D060766:Drinking Water / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005374:Filtration; D006861:Hydrogen Peroxide / Q000737:chemistry; D049449:Luminescence; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D014462:Ultrafiltration / Q000379:methods; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D004128:Dimethylnitrosamine; D060766:Drinking Water; D006861:Hydrogen Peroxide; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Chemiluminescence; N-nitrosamines; N-nitrosodimethylamine (NDMA); Potable water reuse; Real-time analysis; Reverse osmosis