Ferreyra R E, Camiña J M, Marchevsky E, Luco J M
Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Argentina.
Fresenius J Anal Chem. 2000 Nov;368(6):595-600. doi: 10.1007/s002160000549.
A simple and fast analytical pocedure is proposed for the simultaneous spectrophotometric determination of lanthanum, holmium and manganese in synthetic ceramics, (La(0.8-x) Hox Sr0.2 MnO3), by using the partial least-squares (PLS) method. As chromogenic agent 5-Br-PADAP [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol] was used, which form colored complexes with the three elements studied. To avoid metal hydrolysis, a mixture of ethanol and Triton X-100 at pH 9.5 was used for all experiments. A set of 17 calibration solutions measured throughout the 400-700 nm wavelength range was used in the calibration step. The concentration range for Mn(II) was 1-12 x 10(-6) mol L-1, while the range for the rare earth elements La(III) and Ho(III) was 2-8 x 10(-6) mol L-1. In order to demonstrate the applicability of the proposed method, a set of artificial samples containing the three analytes in variable proportions was prepared and analyzed. The analytical results obtained were quite acceptable with relative errors not greater than 7% in most cases.
提出了一种简单快速的分析方法，采用偏最小二乘法（PLS）同时分光光度法测定合成陶瓷（La(0.8-x)HoxSr0.2MnO3）中的镧、钬和锰。使用5-Br-PADAP[2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚]作为显色剂，它与所研究的三种元素形成有色络合物。为避免金属水解，所有实验均在pH 9.5的乙醇和Triton X-100混合物中进行。在校准步骤中使用了一组在400 - 700 nm波长范围内测量的17种校准溶液。Mn(II)的浓度范围为1 - 12×10(-6) mol L-1，而稀土元素La(III)和Ho(III)的浓度范围为2 - 8×10(-6) mol L-1。为了证明所提方法的适用性，制备并分析了一组含有不同比例三种分析物的人工样品。所获得的分析结果相当令人满意，大多数情况下相对误差不大于7%。
