PRIMAQUIN AS A REAGENT IN INORGANIC ANALYSIS Ⅰ. DETECTION OF CERIUM (Ⅳ)
WEI FU-SHENG ZHU YU-RUI SHEN NAI-XUI (Department of Chemistry, The China University of Science and Technology, Hefei)
Primaquin in the presence of 0.1 N sulfuric acid reacts with cerium (Ⅳ) to give a brightly red-violet coloration which is insoluble in ordinary organic solvents (18 organic solvents have been tested). The optimum conditions and selectivity of the colour reaction have been investigated in detail. The identification and concentration limits on spot plate have been found experimentally to be 0.5μg and 1:10~5, respectively. The limits of proportion of cerium (Ⅳ) with 47 cations and 26 anions have also been determined, and in most cases, they neither affect the reaction nor decrease the sensitivity even in the ratios of 1:500, 1:200 and 1:100. Gold (Ⅲ) and most reducing ions interfere with the detection of cerium (Ⅳ). Fluoride masks the colour reaction too. Procedures which have been devised for detection of cerium (Ⅳ) in the presence of gold (Ⅲ) and in a mixture of rare earth oxides are found to be sensitive, highly selective and practically useful.