摘要
Ionic liquids(ILs)are a class of solvents increasingly used as"green chemicals."Widespread applications of ILs have led to concerns about their accidental entry to the environment.ILs have been assessed for some environmental impacts;however,little has been done to characterize their potential impacts on drinking water if ILs accidentally enter surface water.IL cations are often aromatic or alkyl quaternary amines that resemble structures of previously confirmed N-nitrosamine(NA)precursors.Therefore,this study has evaluated two common ILs,1-ethyl-3-methylimidazolium bromide(EMIm Br)and 1-ethyl-1-methylpyrrolidinium bromide(EMPyr Br),for their NA formation potential.Each IL species was reacted with pre-formed monochloramine under various laboratory conditions.The reaction mixtures were extracted using liquid–liquid extraction and analyzed for NAs using high performance liquid chromatography tandem mass spectrometry.At low concentration of IL(250μmol/L),the yields of NAs(NMEA or NPyr)increased with increasing doses of monochloramine from both IL species.The total NA yield was as high as 2.5±0.3 ng/mg from EMIm Br,and as high as 8.6±0.8 ng/mg from EMPyr Br.At high concentration of IL(5 mmol/L),the NA yield reached a maximum at 2.5 mmol/L NH2Cl,and then decreased with subsequent increases in the reactant concentrations,demonstrating ILs’solvent effects.This study re-emphasizes the importance of preventing discharge of ILs to water bodies to prevent secondary impacts on drinking water.
Ionic liquids（ILs） are a class of solvents increasingly used as "green chemicals." Widespread applications of ILs have led to concerns about their accidental entry to the environment.ILs have been assessed for some environmental impacts;however,little has been done to characterize their potential impacts on drinking water if ILs accidentally enter surface water.IL cations are often aromatic or alkyl quaternary amines that resemble structures of previously confirmed N-nitrosamine（NA） precursors.Therefore,this study has evaluated two common ILs,1-ethyl-3-methylimidazolium bromide（EMIm Br） and 1-ethyl-1-methylpyrrolidinium bromide（EMPyr Br）,for their NA formation potential.Each IL species was reacted with pre-formed monochloramine under various laboratory conditions.The reaction mixtures were extracted using liquid–liquid extraction and analyzed for NAs using high performance liquid chromatography tandem mass spectrometry.At low concentration of IL（250 μmol/L）,the yields of NAs（NMEA or NPyr） increased with increasing doses of monochloramine from both IL species.The total NA yield was as high as 2.5 ± 0.3 ng/mg from EMIm Br,and as high as 8.6 ± 0.8 ng/mg from EMPyr Br.At high concentration of IL（5 mmol/L）,the NA yield reached a maximum at 2.5 mmol/L NH2Cl,and then decreased with subsequent increases in the reactant concentrations,demonstrating ILs’ solvent effects.This study re-emphasizes the importance of preventing discharge of ILs to water bodies to prevent secondary impacts on drinking water.
基金
the support of this study by grants from the Natural Sciences and Engineering Research Council of Canada and Alberta Health
