新显色剂二溴对甲基偶氮溴磺的合成及其与铅显色反应的研究

Synthesis of a new chromogenic reagent dibromo-p-methyl-bromosulfonazo(DBMBSA)and its color reaction with lead

报道了新显色剂二溴对甲基偶氮溴磺的合成方法。研究了在酸性介质中 ,新显色剂与铅的反应 ,在 0 .2 4 mol· L- 1磷酸介质中 ,显色剂与铅 ( )形成 2∶ 1蓝色配合物 ,其最大吸收波长为 638nm,表观摩尔吸光系数为 8.4 4× 1 0 4L·mol- 1 ·cm- 1 ,铅含量在 0～ 2 5μg/2 5m L范围内符合比耳定律。拟定的方法用于铜合金中微量铅的测定 。

The method of synthesis of the new chromogenic reagent dibromopmethylbromosulfonazo (DBMBSA) and its color reaction with lead have been investigated.The reagent forms a 2∶1 blue complex with lead in 0.24 mol·L -1 H 3PO 4 medium,having a maximum absorption at 638 nm with an apparent molar absorptivity of 8.44×104 L·mol -1 ·cm -1 .Beer′s law is obeyed for 0~25 μg of lead in 25 mL solution.The method has been applied to the determination of micro amounts of lead in copper alloys with satisfactory results.