Determination of Cobalt (II), Copper (II), Lead (II), and Zinc (II) with Preconcentration by 8-Hydroxyquinoline-Coated Magnetic Nanoparticles (MNPs) and Microinjection Sampling–Flame Atomic Absorption Spectrometry (MIS–FAAS)

Abstract

The separation and preconcentration for trace cobalt(II), copper(II), lead(II), and zinc(II) were investigated with magnetic solid phase extraction using Fe3O4 nanoparticles coated with 8-hydroxyquinoline as a new adsorbent prior to their microinjection sampling–flame atomic absorption spectrometric (MIS–FAAS) determination. The synthesized 8-hydroxyquinoline-coated Fe3O4 magnetic nanoparticles (Fe3O4-8HQ MNPs) were characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The analytical parameters including pH, type of eluent, eluent volume, eluent concentration, adsorption and desorption times, mass of adsorbent, and foreign ion effects were investigated. The analyte ions were quantitatively recovered at pH 8.0 and eluted with 1 M nitric acid. The developed method was applied to pharmaceuticals, wastewater, and a composite material with recoveries from 92% to 98%. The method was validated using NIST certified reference material (CRM) QCP-QCS-1. The results of the CRM solution were compared with those obtained by inductively coupled plasma–mass spectrometry (ICP–MS) and shown to be compatible.