Mathematical Analysis of an Ion Chromatography Determination for Trace Level Perchlorate in Drinking Water

Abstract:

Mathematical analysis of ICS1000+AS20 ion chromatography (IC) determination for trace level (2~50µg•L-1) perchlorate (ClO4-) in water was investigated to optimize the instrument operating conditions and provide a lower detection limit. The Cochran test results reveal the homoscedasticity of the IC determination. The Lack of Fit (LOF) test results show that the operating conditions of AS16 column are not suitable for AS20. The recommended operating conditions of IC determination are 100 mA suppressor current, 35 mmol•L-1 eluent concentration, 1.0 mL•min-1 flow rate, and the standards are arranged in a random order. Method detection limit (MDL) yields a less reliable detection limit than detection limit from the calibration curve (DTC). The MDL of IC determination for trace level ClO4- is 0.890µg•L-1 and the DTC is 1.627 µg•L-1 under recommended operating conditions.