Vachirapatama N, Macka M, Paull B, Münker C, Haddad P R
Separation Science Group, School of Chemistry, University of Tasmania, Hobart, Australia.
J Chromatogr A. 1999 Jul 30;850(1-2):257-68. doi: 10.1016/s0021-9673(99)00143-0.
A method for the simultaneous separation and determination of Nb(V) and Ta(V) as ternary complexes formed with 4-(2-pyridylazo)resorcinol (PAR) and citrate was developed using ion-interaction reversed-phase high-performance liquid chromatography on a C18 column. Method parameters, such as pre-column complex formation conditions and composition of the complexes were investigated using spectrophotometry and HPLC. Under the optimum conditions, the Nb(V) and Ta(V) complexes were eluted within 12 min with a mobile phase of methanol-water (32:68, v/v) containing 5 mM acetate, 5 mM TBABr and 5 mM citrate buffer at pH 6.5, with detection at 540 nm. A typical separation efficiency was 33,000 and 20,000 theoretical plates per metre for Nb(V) and Ta(V), respectively. The relative standard deviation of retention times for the Nb(V) and Ta(V) complexes were 0.16% and 0.17% and for peak areas were 0.28% and 1.36%, respectively. The detection limits (signal-to-noise ratio = 3) for Nb(V) and Ta(V) were 0.4 ppb and 1.4 ppb, respectively. Results obtained for standard reference rock samples agreed well with certified values and results obtained by inductively coupled plasma MS.
建立了一种使用离子相互作用反相高效液相色谱法在C18柱上同时分离和测定与4-(2-吡啶偶氮)间苯二酚（PAR）和柠檬酸盐形成的三元配合物中的铌(V)和钽(V)的方法。使用分光光度法和高效液相色谱法研究了柱前配合物形成条件和配合物组成等方法参数。在最佳条件下，铌(V)和钽(V)配合物在12分钟内被洗脱，流动相为含5 mM乙酸盐、5 mM四丁基溴化铵和5 mM柠檬酸盐缓冲液（pH 6.5）的甲醇-水（32:68，v/v），检测波长为540 nm。铌(V)和钽(V)的典型分离效率分别为每米33,000和20,000理论塔板数。铌(V)和钽(V)配合物保留时间的相对标准偏差分别为0.16%和0.17%，峰面积的相对标准偏差分别为0.28%和1.36%。铌(V)和钽(V)的检测限（信噪比=3）分别为0.4 ppb和1.4 ppb。标准参考岩石样品的测定结果与认证值以及电感耦合等离子体质谱法得到的数据吻合良好。
