title: Determination of perchlorate at trace levels in drinking water by ion-pair extraction with electrospray ionization mass spectrometry.
abstract: Perchlorate has been added to the U.S. Environmental Protection Agency's Drinking Water Contaminant Candidate List (CCL). The present work describes the analysis of perchlorate in water by liquid-liquid extraction followed by flow injection electrospray mass spectrometry (ESI/MS). Cationic surfactants, mostly alkyltrimethyl-ammonium salts, are used to ion-pair aqueous perchlorate, forming extractable ion pairs. The cationic surfactant associates with the perchlorate ion to form a complex detectable by ESI/MS. The selectivity of the extraction and the mass spectrometric detection increases confidence in the identification of perchlorate. The method detection limit for perchlorate based on 3.14 sigma n-1 of seven replicate injections was 100 ng L-1 (parts per trillion). Standard addition was used to quantitate perchlorate in a drinking water sample from a contaminated source, and the concentration determined agreed within experimental error with the concentration determined by ion chromatography.
authors.affiliation: National Risk Management Research Laboratory, United States Environmental Protection Agency, Cincinnati, Ohio 45268, USA. Magnuson.Matthew@epamail.epa.gov
authors.forename: M L
authors.initials: ML
authors.lastname: Magnuson
authors.forename: E T
authors.initials: ET
authors.lastname: Urbansky
authors.forename: C A
authors.initials: CA
authors.lastname: Kelty
mesh_terms: D017022:Flow Injection Analysis; D013058:Mass Spectrometry / Q000379:methods; D010472:Perchlorates / Q000032:analysis*; D017670:Sodium Compounds / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D010472:Perchlorates; D017670:Sodium Compounds; C031068:sodium perchlorate