United States Environmental Protection Agency perchlorate method 332.0 via microbore and capillary chromatographic...

A statistically sound evaluation is made of the United States Environmental Protection Agency's perchlorate Method 332.0 by tandem ion chromatography-mass spectrometry-mass spectrometry. Two microbore formats and one capillary format are used with a deionized-water matrix. The evaluation is made for raw peak-area data and for analyte responses scaled by the internal standard, over an analyte concentration range of 0.25 to 200 microg/L. Results indicate that: (i) the internal-standard signal is suppressed by the analyte in both microbore formats; (ii) the analyte signal is not affected by the internal standard; (iii) models for the calibration curves usually contain bias; (iv) the measurement uncertainty is similar in magnitude for both the peak-area- and ratio-based curves.