Derivative Spectrophotometric Determination of Nd, Ho and Er in Rare Earth Mixtures with 1-Ethyl-6,8-difluoro-7-(3-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-3-quinoline carboxylic acid
文摘
The second derivative spectrophotometric method has been developed as a procedure for the determination of neodymium, holmium and erbium in mixed rare earths. It was found that the 1-ethyl-6, 8-difluoro-7-(3-methyl-1-piperazinyl)-4-oxo-1,4- dihydro-3-quinoline carboxylic acid forms stable complexes with neodymium, holmium and erbium ions in the pH 9.2–10.5 range. In the second derivative spectra the optimum analytical signals for neodymium, holmium and erbium are at 576.2 (+)−574.5 (−)nm, 444.2 (+) −447.8 (−)nm and 516.0 (+) −517.2(−)nm, respectively. Beer’s law is obeyed from 5.0¡Á10−5 M to 2.5¡Á10−4 M of neodymium, holmium and erbium. The quantification limits (10 Sb) were 1.2¡Á10−5 M for Nd, 9.7¡Á10−5 M for Ho and 3.0¡Á10−6 M for Er.
