Plasmochin in the presence of 0.1 N perchloric acid and 8% oxalic acid reacts with Ce(Ⅳ),Au(Ⅲ) and Ⅴ(Ⅴ) to give a redviolet coloration which is insoluble in ordinary organic solvents (17 organic solvents have been tested).The identification and concentration limits both on spot plate and in centrifuge tube have been determined.The limits of proportion of Ce(Ⅳ),Au(Ⅲ) and Ⅴ(Ⅴ) with 23 canons and 25 anions have been determined and in most cases,they neither affect the reaction nor decrease the sensitivity even present in 1000-fold amounts.Procedures for detection of Ce(Ⅳ),Au(Ⅲ) and Ⅴ(Ⅴ) have been devised,which are sensitive and highly selective.