离子色谱法测定饮用水中痕量高氯酸根的数理分析

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

摘要:

采用ICS1000+AS20离子色谱(Ion Chromatography, IC)法测定水中痕量（2~50µg•L-1）高氯酸根（ClO4-）并对实验数据进行数理分析，以优化仪器操作条件，降低检测限。Cochran检验法证明IC法测定痕量ClO4-的方差齐性较好。缺适度（Lack of Fit，LOF）检验分析指出，AS16柱推荐的操作条件并不适用于AS20，标准曲线制定的最佳条件为：抑制电流100 mA，淋洗液浓度35 mmol•L-1，流速1.0 mL•min-1，标样测定随机。采用根据标准曲线推算的检测限（Detection limit from the calibration curve，DTC）衡量仪器检测限比方法检测限（Method detection limit，MDL）更为准确。上述优化条件下IC法测定痕量ClO4-的MDL和DTC分别为0.890µg•L-1和1.627 µg•L-1。

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.