荧光光度法直接测定高纯氧化钕中的痕量镨和铈

DIRECT DETERMINATION OF TRACE PRASEODYMIUM(Ⅱ) AND CERIUM(Ⅲ) IN HIGH PURITY Nd2O3 BY FLUOROPHOTOMETRY

使用P-E LS 50荧光光谱仪,在盐酸介质中,用同一激发波长(214nm)激发,分别测定 Pr(Ⅲ)(283urn)和Ce(Ⅲ)(356nm)发射峰强度.线性范围Pr_6O_11为0.20～15μg·ml^(-1);CeO_2为0.01～0.25μg·ml^(-1).检出限Pr_6O_(11)为0.008μg·ml^(-1);CeO_2为0.0011μg·ml^(-1).讨论了盐酸浓度、仪器带通、荧光稳定性及基体氧化钕对错铈测定的影响.结果表明,仪器带通选择B_(ex)=4.0nm,B_(em)=20.0nm及盐酸浓度为8+92时,Pr(Ⅲ)和Ce(Ⅲ)有较稳定的荧光强度,且基体氧化钛对镨铈测定无影响.用此法直接测定高纯氧化钕样品中痕量镨铈,结果令人满意.

It is reported in this paper that the optimum condition for the fluorophotometric determination of Pr( ? ) and Ce( ? ) in high purity Nd2O3 is studied thoroughly, and it is found that when the sample is excited at the same wave length of 214nm, the emission intensities at their peak wave lengths of 283nm for Pr( ? ) and of 356nm for Ce( ? ) keep a linear relationship with their concentration in the range of 0. 20~ 15礸 ?ml_(-1) and 0. 01~0. 25礸 ?ml_(-1) for Pr6O_(11) and CeO2 respectively. The limit of detection is 0. 008礸 ?ml_(-1) for Pr6O_(11) and 0. 0011礸 ?ml_(-1) for CeO2. It is proved that the fluorescence intensities of Pr( ? ) and Ce(? ) are quite stable in HC1 (8 + 92) medium which is the optimum acidity; the matrix Nd2O3 has no influence on the determi-nation; and the band widths for excitation wave length (B_(ex)) and for emission wave length (Bem) chosen are 4. Onm and 20. Onm respectively for the Luminescence Spectrometer LS 50. The pro-posed method has been applied to the determination of Pr ( ? ) and Ce ( ? ) in high purity Nd2O3 samples with satisfactory results.