DBS-偶氮氯膦分光光度法测定铅的研究

Study on the Spectrophotometric Determination of Lead with DBS-Chlorophosphonazo.

为了克服用双硫腙比色法测环境样品中铅的选择性差和条件要求严等缺点,研究了铅与DBS-偶氮氯膦的显色反应,并提出了用分光光度测定铅的新方法.在稀盐酸介质中,铅与DBS-偶氮氯膦形成1∶2的蓝色配合物,最大吸收波长位于635 nm,表观摩尔吸光系数为4.7×10~4 L·mol^(-1)·cm^(-1),铅量在0—25μg/25ml范围内符合比耳定律.应用于化妆品及铜冶炼烟尘中铅的测定,获得了满意的结果。

In acidic solution, lead forms a blue eolour complex with DBS-chlorophosphonazo. This complex exhibits absorption maximum at 635 nm with apparent molar absorptivity of 4.7×10~4 L·mol^(-1)·cm^(-1). The molar ratio of lead to DBS-Chlorophosphonazo has been found to be 1 : 2. Beer' s law is obeyed in the concentration range of 0—20 μg per 25 ml. This colour reaction has been used directly for the spectrophotometrie determination of lead in cosmetics and dust of smelting copper with satisfactory resuits.