测定纯铅中杂质铋的马钱子碱-碘化钾萃取标准比色法,手续繁琐,使用不便。2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)光度法也需经过萃取分离。我们在文献的基础上,利用EDTA消除基体铅和其它共存元素的影响,以铋-5-Br-PADAP配合物吸附波直接测定了纯铅中的铋。方法简便、灵敏、准确,相对标准偏差小于5％,铋的回收率为97～105％。 一、仪器和主要试剂 Determination of pure lead in bismuth impurities in strychnos - potassium iodide extraction standard colorimetric procedures complicated, inconvenient to use. 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol (5-Br-PADAP) spectrophotometry also need to be extracted. Based on the literature, we used EDTA to eliminate the influence of matrix lead and other coexisting elements, and the bismuth in pure lead was directly determined by the adsorption wave of bismuth-5-Br-PADAP complex. The method is simple, sensitive and accurate. The relative standard deviation is less than 5% and the recovery rate of bismuth is 97 ~ 105%. First, the instrument and the main reagent