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铜合金中做为主量元素铅的络量分析,很早已有介绍。Kinnunen 推荐使用 EDTA-Mn 盐为置换剂,铬黑 T 指示剂直接滴定铜合金中铅。但所测结果为铅锰总量。后来又提出加入二乙基代氨基甲硫羟羰酸钠释放出 EDTA 的方法,但试剂和铅生成的白色沉淀影响终点观察。特别是对于铅的分析,终点观察稍有不慎就会产生较大的误差。利用硫酸盐以及其它沉淀剂分离出铅之后再进行络量分析,能得到较高的准确度,可惜在操作上增加了手续。很少能体现出络量分析的优越性。
Copper alloy as a major element of lead volume analysis, has long been introduced. Kinnunen recommends EDTA-Mn salts as displacer and chromium black T indicator for direct titration of lead in copper alloys. However, the test results for the total amount of lead and manganese. Later it was proposed to add EDTA to release EDTA, but the white precipitate formed by the reagents and lead affected the end point. Especially for the analysis of lead, the end point to observe a slight mistake will have a greater error. The use of sulfate and other precipitants isolated lead after the volume analysis, can get a higher accuracy, but unfortunately in the operation of an increase of procedures. Rarely reflect the superiority of the volume analysis.