Structural elucidation of disinfection by-products in treated drinking water.
Two unusual disinfection by-products have been detected periodically in the gas chromatography/mass spectrometry (GC/MS) characterization analyses of semi-volatile organics in treated drinking water. The electron ionization (EI) mass spectra contained mono-chlorinated and mono-brominated ions at m/z 107/109 and 151/153, respectively. Library searching techniques suggested mono-halogenated butanol structures but no matches could be found. Positive ion chemical ionization (CI) spectra contained mono-chlorinated and mono-brominated ions at m/z 105/107 and 149/151, respectively. No [M + H]+ ions were initially observed. Accurate mass measurements confirmed the empirical formulae for the significant ions in the EI spectra and the mono-halogenated butanol structures. Further CI experiments with other reagent gases and instruments revealed possible molecular weights of 139 and 183 Da, respectively. Tandem mass spectrometry (MS/MS) experiments in EI and CI were used to elucidate the fragmentation schemes. The two compounds have been tentatively identified as 1-aminoxy-1-chlorobutan-2-ol and 1-aminoxy-1-bromobutan-2-ol, respectively.
Ministry of the Environment, Laboratory Services Branch, Etobicoke, ON, M9P 3V6, Canada. vince.taguchi@ene.gov.on.ca
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D020001:1-Butanol / Q000737:chemistry* / Q000302:isolation & purification; D000440:Butanols; D002724:Chlorobutanol / Q000031:analogs & derivatives / Q000737:chemistry* / Q000302:isolation & purification; D002849:Chromatography, Gas; D004202:Disinfectants / Q000737:chemistry / Q000627:therapeutic use; D004203:Disinfection / Q000379:methods*; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization; D014881:Water Supply / Q000032:analysis*
C426464:1-aminoxy-1-bromobutan-2-ol; C426463:1-aminoxy-1-chlorobutan-2-ol; D000440:Butanols; D004202:Disinfectants; D020001:1-Butanol; D002724:Chlorobutanol