固体废物氰化物总量和浸出毒性测定方法的比较

Comparison of Determination Methods for Total Content and Extraction Toxicity of Cyanide in Solid Waste

中国现行的固体废物氰化物总量和氰化物浸出毒性的分析方法存在缺陷,不便于广泛指导监测工作,笔者优化了固体废物氰化物测定的前处理方法,明确了固体废物氰化物总量、氰化物浸出毒性测定时的样品粒径、浸提方法和消解方法,建立了容量法、分光光度法、流动注射法测定固体废物氰化物总量和浸出毒性的方法,并与标准方法(离子色谱法)进行比较。实验结果表明:容量法、分光光度法、流动注射法测定结果与离子色谱法无显著差异,3种方法测定固体废物氰化物总量加标回收率为80.5%~102%,平行样测定相对标准偏差为3.0%~6.9%,3种方法测定固体废物氰化物浸出毒性加标回收率为80.1%~107%,平行样测定相对标准偏差为7.8%~9.5%,3种方法测定结果精密度和准确度良好,均能够满足固体废物氰化物总量和氰化物浸出毒性的测定要求。其中容量法、分光光度法由于其仪器设备简单、操作简便,可用于突发环境事件应急监测等情况下固体废物氰化物的测定。但容量法检出限较高,不能满足评价标准较低的分析测试工作要求,离子色谱法、分光光度法和流动注射法检出限均能满足一般分析测试要求。

The standard methods for the determination of total content and extraction toxicity of cyanide in solid waste are flawed in China,which are not convenient to guide the actual monitoring work.By condition experiment,the pretreatment methods for the determination of cyanide in solid waste were optimized,including sample particle size,extraction methods,and digestion methods.In this study,the titration method,spectrophotometry,and flow injection method for determination of total cyanide and cyanide extraction toxicity in solid waste were established and compared with the standard method(ion chromatography).The results show that there was no significant difference between four methods.The recoveries of total cyanide in solid waste by three methods were in the range of 80.5%-102%,the RSDs of parallel sample determination were 3.0%-6.9%.The recoveries of cyanide extraction toxicity in solid waste by three methods were in the range of 80.1%-107%,the RSDs of parallel sample determination were 7.8%-9.5%.The three methods have good accuracy and precision,which can meet the requirements of the determination of total cyanide and cyanide extraction toxicity in solid waste.The titration method and spectrophotometry can be used for the determination of cyanide in solid waste under the conditions of insufficient laboratory instruments such as environmental emergency monitoring due to their simple equipment and simple operation.But the titration method has a higher detection limit and can not meet the analytical test work with a lower evaluation standard.The detection limits of other three analytical methods can meet the general detection requirements.