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Sorption and desorption of organic matter on solid‐phase extraction media to isolate and identify N ‐nitrosodimethylamine precursors
Author(s) -
Hanigan David,
Liao Xiaobin,
Zhang Jinwei,
Herckes Pierre,
Westerhoff Paul
Publication year - 2016
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201600139
Subject(s) - n nitrosodimethylamine , sorption , solid phase extraction , desorption , extraction (chemistry) , chemistry , chromatography , phase (matter) , environmental chemistry , adsorption , organic chemistry , carcinogen
#x02010;Nitrosodimethylamine is mutagenic in rodents, a drinking water contaminant, and a byproduct of drinking water disinfection by chloramination. Nitrosodimethylamine precursor identification leads to their control and improved understanding of nitrosodimethylamine formation during chloramination. Mass balances on nitrosodimethylamine precursors were evaluated across solid‐phase extraction cartridges and in eluates to select the best combination of solid‐phase media and eluent that maximized recovery of nitrosodimethylamine precursors into a solvent amenable to time‐of‐flight mass spectrometry analysis. After reviewing literature and comparing various solid‐phase cartridges and eluent combinations, a method was obtained to efficiently recover nitrosodimethylamine precursors. The approach with the greatest recoveries of nitrosodimethylamine precursors involved cation exchange resin loaded with water samples at pH 3 and eluted with 5% NH 4 OH in methanol. This indicated that nitrosodimethylamine precursors are amines that protonate at low pH and deprotonate at high pH. Quaternary amines were irreversibly sorbed to the cation exchange cartridge and did not account for a large fraction of precursors. Overall, a median recovery of 82% for nitrosodimethylamine precursors was achieved from 11 surface waters and one wastewater. Applying this method allowed discovery of methadone as a new nitrosodimethylamine precursor in wastewater effluent and drinking water treatment plant intakes.