研究了显色剂 DBS-偶氮氯膦与铋的最佳显色条件。在 0 .2 mol·L- 1 的硫酸介质中 ,铋与 DBS-偶氮氯膦形成稳定的 1∶ 2的蓝紫色配合物 ,其最大吸收峰为 640 nm,表观摩尔吸光系数为1 .3× 1 0 5。当铋含量在 0～ 1 5μg/2 5ml范围内符合比耳定律 ,相关系数为 0 .9989。方法灵敏度高 ,选择性好 ,应用于合金钢与水样中铋的测定 ,加入回收率为 91 %～ 1 0 5%。 The best color conditions of DBS-chlorophosphonazo and bismuth were studied. In 0.2 mol·L -1 sulfuric acid medium, bismuth and DBS-chlorophosphonazo form a stable 1: 2 blue-violet complex with the maximum absorption peak at 640 nm and an apparent molar absorption coefficient of 1. 3 × 10 5. Beer’s law is obeyed when bismuth content is in the range of 0-1 5μg / 2 5ml, and the correlation coefficient is 0.9989. The method has high sensitivity and good selectivity, and is applied to the determination of bismuth in alloy steel and water samples with the recovery of 91% ~ 105%.