Preconcentration and simultaneous multicomponent spectrophotometric determination of lead and cadmium using modified maghemite nanoparticles by WOSC-PLS and OSC-PLS

A novel and fast solid phase extraction method for simultaneous preconcentration and determination of lead and cadmium ions in real samples was developed by using sodium dodecyle sulphate-coated maghemite nanoparticles (SDS-coated γ-Fe2O3 NPs) as a new extractor. The chemical co-precipitation method was used in the preparation of the γ-Fe2O3 NPs. The maghemite nanoparticles were synthesized according to a method proposed elsewhere [1]. The coating of nanoparticles by SDS was performed according to the method proposed elsewhere [2]. After preconcentration, the absorbance of the extracted ions was measured using tiazolylazo-Resorsinol (TAR) as a complexation reagent in the wavelength range of 300–700 nm. The influence of effective parameters on the separation and preconcentration of the analytes, such as amount of adsorbent, pH, amount of SDS, contact time, volume and concentration of eluent and extraction volume were investigated. PLS modeling is a powerful multivariate statistical tool and can be performed with easily accessible statically software. The basic concept of PLS was originally described by Wold et al. and consequently different application for PLS modeling were reported [3]. The wavelet orthogonal signal correction with the partial least squares (WOSC-PLS) method was then applied for simultaneous determination of adsorbed metal ions. Under optimized conditions, the calibration curves were linear in the range of 0.2 - 4.7 and 0.04 -3.02 μg L−1 for Pb (II) and Cd (II), respectively. Limits of detection and enrichment factors for lead and cadmium were 0.039-0.019 μgL−1 and 240-250, respectively. The proposed method was successfully applied for the simultaneous determination of lead and cadmium in drink samples.