Simultaneous Spectrophotometric Determination of La, Ho, Mn 5-Br-PADAP Complexes Using Multivariate Calibration with Partial Least-Squares (PLS) Data Evaluation

R.E. FERREYRA; J. M. CAMIÑA; E. J. MARCHEVSKY; J. M. LUCO

FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY

Springer-Verlag GmbH

Año: 2000 vol. 368 p. 595 - 600

0937-0633

A simple and fast analytical pocedure is proposed for the simultaneous spectrophotometric determination of lanthanum, holmium and manganese in synthetic ceramics, 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 millimol L-1, while the range for the rare earth elements La(III) and Ho(III) was 2?8 millimol 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.