二苯碳酰二肼分光光度法及其改进方法测定水体中Cr(Ⅵ)

Diphenylcarbohydrazide spectrophotometry and its improved methods for the determination of chromium( Ⅵ)

采用3种方法对水体中Cr(Ⅵ)进行测定。方法一为二苯碳酰二肼分光光度法,方法二和方法三则对其进行改进。方法二以1+7硫酸代替两种酸性溶液,测定时加入酸性溶液与显色剂。方法三以乙醇(95%)代替丙酮,并将酸性溶液与显色剂混合,测定时加入。结果表明,3种方法所测定的标准曲线几乎一致,且线性相关性较好,精密度较高,均可用于水体中Cr(Ⅵ)的测定。其中方法三更加方便快捷,操作无毒害。

Three methods were used to detected Cr（ Ⅵ） in water. Method 1 is spectrophotometry with diphenylcarbazide as color reagent,method 2 and method 3 are improved on the basis of method 2. Method2 replaced two acidic solution with 1 ＋ 7 sulfuric acid,then added acidic solution and color reagent when detected Cr（ Ⅵ）. Method 3 replaced acetone with ethanol（95%）,then mixed the acidic solution with the color reagent,added the mixture when detected Cr（ Ⅵ）. The results showed that the standard curves of the three methods are almost the same,and the linear correlation is good,the precision is high,which can be used for the determination of Cr（ Ⅵ） in water. Particularly,method 3 is more convenient and efficient,and it is a kind of non-toxic operation.