K比例H点标准加入吸光光度法同时测定矿样中铌和钽
Simultaneous Determination of Niobium and Tantalum in Ore Samples by K-ratio H-point Standard Addition Spectrophotometry
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摘要: 在盐酸介质中,水杨基荧光酮-氯化十六烷基吡啶体系虽然能分别和铌、钽发生灵敏的络合反应,但所形成的三元胶束络合物的光谱严重重叠,一不适合同时测定铌和钽。文章采用K比例H点标准加入分光光度法,结合Origin 7.5软件,选择最佳波长对,探讨了在不经化学分离的情况下,同时测定矿样中铌和钽的方法。结果表明,K比例H点标准加入法很好地解决了铌和钽的光谱干扰问题,得到了待测物的浓度,还对干扰物质的浓度进行估算。在最佳试验条件下,铌和钽的线性范围分别为(0.4~5.8)×10-5 g/L、(0.4~11.2)×10-5 g/L,方法检出限分别为0.28 μg/L、0.22 μg/L,测定精密度分别为0.54%~0.88%、0.88~1.52%。方法用于样品中铌和钽的同时测定,测定值与参考值相符。Abstract: In chloride acid medium salicyl fluorone-cetyl pyridinium could react with niobium (Nb) and tantalum (Ta) respectively to form ternary micelle complexes, but the complexes exhibit serious spectrum overlap and are not used for spectrophotometric determination of Nb and Ta. In this paper, a new method for simultaneous determination of Nb and Ta in ore samples by K-ratio H-point standard addition spectrophotometry (HPSA) without chemical separation was reported. The optimum wavelength pairs were selected by home-made procedure in Origin 7.5 software. The spectrum interference on determination of Nb and Ta could be eliminated using K-ratio HPSA method. Under the optimum conditions, the linear ranges of determination for Nb and Ta were (0.4~5.8)×10-5g/L and (0.4~11.2)×10-5g/L with a detected limit of 0.28 μg/L and 0.22 μg/L respectively. The determination precision were 0.54%~0.88% RSD for Nb and 0.88%~1.52% RSD for Ta. The method has been applied to the simultaneous determination of Nb and Ta in ore samples with satisfactory results.
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