title: Matrix diversion methods for improved analysis of perchlorate by suppressed ion chromatography and conductivity detection.
abstract: Two inline matrix diversion methods were developed for the sensitive analysis of perchlorate in a matrix comprising up to 1000 mg l(-1) of chloride, sulfate and bicarbonate ions using suppressed ion chromatography and conductivity detection. The first method used a cryptand C1 concentrator column, which exhibited a high selectivity for perchlorate ion over the other matrix anions. After retaining the sample anions in a concentrator column derivatized with a crytpand phase, a rinse step was implemented with a weak base to divert the matrix ions to waste while selectively retaining perchlorate in the concentrator column for subsequent analysis. The analysis was done using a 2mm IonPac AS16 or 2 mm IonPac AS20 separator column. The second method was a two-dimensional matrix diversion method with a focus on improving the detection sensitivity. The first dimension was used to achieve some resolution of the matrix ions from perchlorate. The perchlorate ion was then diverted into a concentrator column for subsequent analysis in the second dimension. By pursuing analysis using a 4mm IonPac AS16 or IonPac AS20 column in the first dimension and subsequently pursuing analysis using a 2mm IonPac AS16 or IonPac AS20 column format, excellent sensitivities were achieved when the first and second dimensions were operated at the same linear flow velocity (cm min(-1)). While sensitive detection of perchlorate in the low microg l(-1) regime was achieved by the above methods in the presence of matrix ions, superior recovery for perchlorate was demonstrated under a variety of matrix concentrations by the second method.
authors.affiliation: Dionex Corporation, 445 Lakeside Drive, Sunnyvale, CA 94087, United States.
authors.forename: Rong
authors.initials: R
authors.lastname: Lin
authors.forename: Brian
authors.initials: B
authors.lastname: De Borba
authors.forename: Kannan
authors.initials: K
authors.lastname: Srinivasan
authors.forename: Andy
authors.initials: A
authors.lastname: Woodruff
authors.forename: Chris
authors.initials: C
authors.lastname: Pohl