饮用水中硫化物现场检测方法与实验室方法的比较

Comparison of on-site detection and laboratory method for sulfides in drinking water

目的利用便携式硫化物测定仪对水中硫化物进行现场检测,并与实验室方法[GB/T 5750—2006《生活饮用水标准检验方法》中的N,N-二乙基对苯二胺分光光度(DPD)法]进行比较。方法分别使用国产和进口便携式测定仪与国标方法(DPD法)进行测定,比较水样采集和保存、标准溶液和试剂配制的不同,分析比较两种方法的线性范围、定量下限、精密度和准确度。结果与实验室方法比较,水中硫化物现场检测方法所用仪器内置标准曲线,浓度直读,所以不需要标准溶液的配制过程,并省略了样品采集保存过程。现场检测方法、实验室方法的线性范围分别为0.01~0.5 mg/L、0.01~0.2 mg/L。现场检测方法的定量下限为0.01 mg/L,RSD<7.7%,回收率为70%~94%,与国标方法结果一致。加入适量盐酸羟胺或甘氨酸均可以抑制水中余氯对硫化物测定的干扰。结论生活饮用水中硫化物的现场检测方法具有简便、快速的优势,更适合现场污染物的快速甄别,二种方法可以互为补充。

Objective The portable sulfide detector is used for on-site detection of sulfide in drinking water and compared with DPD method ruled by GB/T5750-2006 Standard Examination Methods for Drinking Water. Methods The domestic and imported portable measuring instruments and DPD method were used for measurement respectively. The differences in water sample collection and preservation,standard solution and reagent preparation were compared,as well as linear range,quantitative lower limit,precision and accuracy. Results The on-site detector presented a built in standard curve, direct reading,free of preparation process of standard solution and process for sample collection and preservation.The linear ranges of field test method and laboratory method was 0.01-0.5 mg/L and 0.01-0.2 mg/L respectively. The quantitative lower limit of field detection method was 0.01 mg/L,RSD〈7.7%,and the recovery rates were 70%-94%,which was consistent with the results of DPD method. The addition of an appropriate amount of hydroxylamine hydrochloride or glycine could inhibit the interference of residual chlorine in water to the determination of sulfide. Conclusion On-site detection method of sulfide in drinking water is simple and rapid,more suitable for rapid screening of pollutants on-site. The two methods can complement each other.