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IMPROVEMENT AND EVALUATION OF METHODS FOR SULFATE ANALYSIS
Citation:
Appel, B., E. Hoffer, M. Haik, W. Wehremeister, AND E. Kothny. IMPROVEMENT AND EVALUATION OF METHODS FOR SULFATE ANALYSIS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/4-79/028 (NTIS PB298148), 1979.
Description:
A simpler and faster procedure for the manual turbidimetric analysis of sulfate has been developed and evaluated. This method as well as a turbidimetric procedure using SulfaVer(R), automated methylthymol blue (MTB) procedures for analysis in the 0-100 micrograms/ml and 0-10 micrograms sulfate/ml ranges, and the Dionex Ion Chromatograph were evaluated for accuracy, precision, working range, interference effects, and degree of agreement using atmospheric samples. Using EPA sulfate audit strips, all methods showed accuracies within 8% of the accepted value, and coefficients of variation with atmospheric samples of = or < 6%. Colloidal clay and yellow, water soluble organics isolated from atmospheric samples caused interference with all methods. All the methods studied provide reliable analyses for 24-hour hi-vol filter samples. The automated MTB method, modified for use in the 0-10 micrograms/ml range as suggested by Colovos, offers excellent potential for analysis of low volume samples such as those provided by a dichotomous sampler network.