Simultaneous spectrophotometric determination of lead, copper and nickel using xylenol orange by partial least squares

A partial least squares (PLS) calibration model was developed for the simultaneous spectrophotometric determination of Pb (ΙΙ), Cu (ΙΙ) and Ni (ΙΙ) using xylenol orange as a chromogenic reagent. The parameters controlling behavior of the system were investigated and optimum conditions were selected. The calibration graphs were linear in the ranges of 0.0–9.091, 0.0–2.719 and 0.0–2.381 ppm for lead, copper and nickel, respectively. The experimental calibration matrix was designed with 21 mixtures of these chemicals. Absorbance data were taken between 350-650 nm and absorbance data were autoscaled. A set of synthetic sample mixtures were used to validate the proposed method. The root mean square errors of predictions (RMSEPs) and percent of relative prediction errors (RSEPs) are 0.2164, 0.0744, 0.0735 ppm and ±7.1855, ± 6.3193, ± 7.0806% for lead, copper and nickel, respectively.