Simultaneous determination of Cobalt, Nickel, Copper and Zinc by multivariate methods partial least square (PLS) and hybrid linear analysis (HLA)

The partial least squares (PLS) and hybrid linear analysis (HLA) applied to the simultaneous determination of the divalent ions of copper, nickel, cobalt and zinc based on the formation of their complexes with solochrome black (SC). The absorption spectra were recorded from 520 through 620 nm. The effect of pH on sensitivity and the selectivity was studied in the range 3.0–8.0 and and the pH 6.5 was choosed according to the absorbance of complex as a function of pH. concentration range for Cu2+, Ni2+, Co2+and Zn2+ in solution calibration sets were 0.2 - 2 ppm. The root mean squares differences (RMSD) for copper, nickel, cobalt and zinc were 0.0492, 0.0625, 0.0592 and 0.0545, respectively. Keywords: Nanofluid; γ-Fe2O3 nanoparticles; Poly(ethylene glycol with molar mass of 400,2000 and 6000 g.mol-1); Rheological properties.