Comparison of Partial Least Squares Regression and H-Point Standard Addition Method for Simultaneous Spectrophotometric Determination of Zinc,Cobalt and Nickel by l-(2-Pyridylazo)2-Naphthol in Micellar Media

摘要

Simultaneous Spectrophotometric methods are described for the determination of Zn~(2+),Co~(2+)and Ni~(2+)by l-(2-pyridylazo)2-naphthol(PAN)in micellar media,using absorbance correction-H-point standard addition method(HPSAM)and partial least squares(PLS)regression.The ligand and its metal complexes,i.e.Zn~(2+)-PAN,Co~(2+)-PAN and Ni~(2+)-PAN,were made water-soluble by the neutral surfactant Triton X-100,and therefore extraction with organic solvents was no longer required.Formation of all of these complexes was complete within 10 min at pH 9.2.The linear range was 0.l-l.5 mg L~(-1)for Zn~(2+),0.1-2.0 mg L~(-1)for Co~(2+)and 0.1-2.0 mg L~(-1)for Ni~(2+).The relative standard deviation(RSD)for the simultaneous determination of 0.50 mg L~(-1)each of Zn~(2+),Ni~(2+)and Co~(2+)by applying the H-point standard addition method was 2.55%,2.04% and 3.70%,respectively.The total relative standard error for applying the PLS method to 9 synthetic samples in the linear ranges of these metals was 1.8%.Interference effects of common anions and cations were studied,and both methods were applied to the simultaneous determination of Zn~(2+),Co~(2+)and Ni~(2+)in alloy samples.