New fluorimetric reagents, sodium pyrophosphate, sodium trimetaphosphate, and sodium tetrametaphosphate, for the determination of cerium(III)

Three sensitive and selective new alternatives for fluorometric determinati on of cerium(III) are described in this study. Ce(III) is highly fluorescen t in sodium pyrophosphate, sodium trimetaphosphate, and sodium tetrametapho sphate solutions. For these reagents, the maximum excitation/emission wavel engths are 300/350, 297/340, and 299/352 nm, respectively. Maximum fluoresc ence intensities are obtained by irradiating Ce(III) dissolved in 0.033 g L -1 sodium pyrophosphate, 41.4 g L-1 sodium trimetaphosphate, and 0.96 g L-1 sodium letrametaphosphate at room temperature. The fluorescence intensitie s are linear over the range 0.001-30,0.001-75, and 0.001-70 mu g ml(-1). Th e detection limits are calculated as 9.5 x 10(-3), 1.1/10(-3), and 3.8 x 10 (-3) mu g ml(-1) Ce(III), respectively. The relative standard deviations fo r 15/0.05 mu g ml(-1) Ce(III) are 1.1/1.2, 1/1.1, and 1.2/1.3%, respectivel y. Quenching effects of other lanthanides and some inorganic anions were in vestigated. The Methods have been applied to rare earth mixtures with a goo d accuracy.