摘要
[背景]电位滴定法在测定耗氧量的过程中依据电位突跃确定滴定终点,相对酸性高锰酸钾滴定法依据目视比色原理判定终点更具客观性。[目的]比较电位滴定法与酸性高锰酸钾滴定法测定饮用水中耗氧量的主要差异。[方法]采用与酸性高锰酸钾滴定法相同的前处理方法,从滴定过程中的加液体积、滴定速度、滴定温度及实际样品测定结果等方面比较两种方法的差异。[结果]电位滴定法最小加液体积更小,滴定速度可控,终点判定依据客观,检测灵敏度、精密度及重现性更高。当样品加标浓度分别为1.40、2.79 mg/L时,电位滴定法的加标回收率为分别为95.1%~107.9%、99.5%~101.0%,相对标准偏差分别为0.9%~3.7%、0.8%~1.2%。耗氧量浓度在5.5 mg/L以内可得到较为准确的检测。[结论]电位滴定法适用于测定饮用水中的耗氧量。
[Background]Using the jump in potential,potentiometric titration method is theoretically more objective in predicting the end points of titrations than acidic potassium permanganate method which is based on visual colorimetry.[Objective]This study compares the main differences between potentiometric titration method and acidic potassium permanganate method in determination of oxygen consumption in drinking water.[Methods]Using the same pretreatment as the acidic potassium permanganate method did,the differences between the two methods were investigated from selected aspects of liquid adding volume,titration speed,titration temperature,and determination results of practical samples.[Results]With smaller liquid adding volume,controllable titration speed,and objective judgment of titration end point,potentiometric titration method had higher sensitivity,precision and reproducibility.When the samples were spiked with standard solution at 1.40 and 2.79 mg/L respectively,the recoveries of the potentiometric titration method were 95.1%-107.9%and 99.5%-101.0%respectively,and the relative standard deviations were 0.9%-3.7%and 0.8%-1.2%respectively.The oxygen consumption were accurately determined within the concentration of 5.5 mg/L.[Conclusion]Potentiometric titration method is suitable for determination of oxygen consumption in drinking water.
作者
裴赛峰
蔡萍
张昀
PEI Sai-feng;CAI Ping;ZHANG Yun(Environmental and Occupational Testing Lab,Shanghai Municipal Center for Disease Control and Prevention,Shanghai 200336,China)
出处
《环境与职业医学》
CAS
CSCD
北大核心
2019年第12期1156-1160,共5页
Journal of Environmental and Occupational Medicine
关键词
电位滴定
耗氧量
酸性高锰酸钾滴定法
potentiometric titration
oxygen consumption
acidic potassium permanganate method
