title: Challenges encountered in extending the sensitivity of US Environmental Protection Agency Method 314.0 for perchlorate in drinking water.
abstract: Concerns about the potential adverse health effects of perchlorate at concentrations below the minimum reporting level (MRL) of US Environmental Protection Agency (EPA) Method 314.0 (generally recognized as 4.0 microg/l) have led to an interest in increasing the sensitivity of the method. This work describes the use of 2 mm columns with a large-loop direct injection method, a column concentration technique and this concentration technique with a background reduction step, to increase the sensitivity for the analysis of trace levels of perchlorate in high ionic strength matrices. The concentrator columns studied were the Dionex TAC LP-1 and a new Dionex high capacity Cryptand concentrator column. The use of a surrogate to monitor trapping efficiency for the concentration technique and the use of confirmational columns to minimize the potential for false positives are also discussed. The large-loop direct injection method and the column concentration methods provided acceptable data when the samples were pre-treated with solid phase pretreatment cartridges. The background reduction technique did not provide acceptable data with either of the concentrator columns evaluated.
authors.affiliation: EFFEX Analytical Services, 2545 Chandler Avenue, Ste 8, Las Vegas, NV 89120, USA.
authors.forename: Herbert P
authors.initials: HP
authors.lastname: Wagner
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Suarez
authors.forename: Barry V
authors.initials: BV
authors.lastname: Pepich
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Hautman
authors.forename: David J
authors.initials: DJ
authors.lastname: Munch
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods / Q000592:standards; D017408:Guidelines as Topic; D009994:Osmolar Concentration; D010472:Perchlorates; D012680:Sensitivity and Specificity; D014481:United States; D014484:United States Environmental Protection Agency; D014881:Water Supply / Q000032:analysis*
chemical_list: D010472:Perchlorates; C494474:perchlorate