A sensitive chromogenic reagent,2-(4-chloro-2-phosphophenylazo)-7-(2,4-dichlorophenylazo)-1,8-dihydroxy-3,6-naphthalene disulfonic acid(abbreviation:DC-CPA),has been used in the spectrophotometric determination of bismuth.

• 研究了2-(4-氯-2-膦酸基苯偶氮)-7-(2；4-二氯苯偶氮)-1；8-二羟基-3；6-萘二磺酸(DC-CPA)与铋的显色反应.