高氯离子对测定地表水中化学需氧量的干扰及消除方法

Interference and Elimination Methods of High Chloride Ions on the Determination of Chemical Oxygen Demand in Surface Water

通过不同实验条件的筛选,向氯离子浓度为1000 mg/L的地表水样品中加入2 mL、100 g/L的硫酸汞后基本可以消除氯离子的干扰。氯离子浓度为2000 mg/L左右的地表水样品,可以采取的前处理方法是加入2 mL、300 g/L的硫酸汞,可以较好地消除氯离子的干扰。氯离子浓度达到3000 mg/L的地表水样品,可以采取的前处理方法为加入3 mL、300 g/L的硫酸汞可以较好消除氯离子的干扰。结果表明,该前处理方法准确可靠,适用于含氯离子浓度1000~3000 mg/L的地表水中COD的测定。

Through the screening of different experimental conditions,the interference caused by chloride ions can be basically eliminated by adding 2 mL and 100 g/L of mercury sulfate to the surface water sample with chloride ion concentration of 1000 mg/L.For surface water samples with chloride ion concentration of about 2000 mg/L,the pre-treatment method can be adopted by adding 2 mL and 300 g/L of mercury sulfate,which can better eliminate the interference caused by chloride ions.For surface water samples with chloride ion concentration of 3000 mg/L,the pretreatment method that can be adopted is to add 3 ml and 300 g/L of mercury sulfate,which can better eliminate the interference caused by chloride ions.The results show that the pretreatment method is accurate and reliable,and can be applied to the determination of COD in surface water with chloride ion concentration of 1000~3000 mg/L.