摘要
运用二苯碳酰二肼分光光度法对水中铬进行测定 ,发现在硫酸介质中 ,Cr6+ 与二苯碳酰二肼形成组成比为3:2的配合物 ,其最大吸收波长位于 5 40nm处 ,表观摩尔吸光系数为 4× 10 4 L·mol-1·cm-1,铬的质量浓度在 0 .0 0 4mgL-1～1.0 0 0mgL-1范围内符合比尔定律 ,相关系数γ =0 .996 9。并对分光光度法的最佳条件 ,包括酸性介质、酸试、试剂用量、显色时间、有色配合物的稳定性及其它离子对测定Cr6+
The reaction of Diphenylcarbonydraide with Cr 6+ in water was studied.In a medium of brimstone acid, Cr 6+ reacts with Diphenylcarbonydratide to form a stable 3:2 chelate,with an apparent molar absorptivity of ε=4×104L·mol -1 ·cm -1 at 540 nm.Beer's law is obeyed in the range of 0.004～1.000mgL -1 ,and the correlation coefficient is 0.9969.The best conditions of spectrophotometry were studied including acid medium,acidity,reagent quantity,color time,the stability of colored com-plex and the disturbances of other ions to Cr 6+ .This method was applied to the detection of Cr 6+ in water.
