Perchlorate in Fertilizers

Abstract : This report documents an inter-laboratory collaborative study on the performance on ion chromatography (IC) methods for perchlorate analysis in lawn and garden fertilizers. Seven government, private, and commercial laboratories participated in the analysis of 34 aqueous suspensions of the test materials, using similar ion chromatography systems. Two method variants (AS-11 and AS-16) were evaluated. Statistical evaluations by paired t-test for the means analysis found good agreements m each of the methods variants and excellent agreement between the methods. The study also found no significant differences the performance of the microbore column with respect to the standard bore column. This report also evaluates and compares the performance of IC with respect to capillary electrophoresis (CE), Raman spectroscopy (RS), and titration for perchlorate analysis. The study found excellent agreement between the ion chromatography and CE results, and little or no agreement between IC and RS or titration. As expected, compared to the IC results, titration is biased high.