铬的测定一般以Cr(Ⅵ)和Cr(Ⅲ)两种形式进行测定.近年来.新显色剂的不断出现,使得以Cr(Ⅲ)形式与显色剂显色测铬的方法也逐渐增多.偶氮氯膦类试剂与Cr(Ⅵ)褪色光度法测铬已有报道,本文所选用的偶氮氯膦类试剂与Cr(Ⅲ)显色测铬未见报道.经研究了五种偶氮氯膦类试剂与Cr(Ⅲ)的显色反应,发现间磺酸基偶氮氯膦(简写CPA-mS)与Cr(Ⅲ)显色体系的灵敏度最高,为此本文系统地研究了CPA-mS与Cr(Ⅲ)显色的最佳条件,用于测定水样中 Determination of chromium is generally Cr (Ⅵ) and Cr (Ⅲ) in two forms of determination.In recent years, the new color agent appears constantly, so that with Cr (Ⅲ) Has been reported.It has not been reported that the chlorophosphonazo reagents and Cr (III) chromophores measured in this paper have not been reported.After five kinds of reagents have been studied, The chromogenic reaction of chlorophosphonates with Cr (Ⅲ) showed that the sensitivity of m-sulfonated chlorophosphonazo (abbreviated CPA-mS) to Cr (Ⅲ) chromogenic system was the highest. The optimal conditions for the color development of CPA-mS and Cr (III) are used in the determination of water samples