Abstract

In this research application of thiol functionalized mesoporous silica coated magnetite nanoparticles was studied as an adsorbent in solid phase extraction for the determination of Cr³⁺, Ag⁺, Co²⁺, Pb²⁺, Zn²⁺, and Cu²⁺ metal ions from water samples using flame atomic absorption spectrometry (FAAS). Magnetic nanoparticles (MNPs) carrying target metals were easily separated with applying an external magnetic field from the aqueous solution. After extraction and collection of MNPs, the metal ions were desorbed with 3 mol L^-1 of the HCl solution containing 2% (w/v) thiourea. Effects of pH, adsorbent amount, contact time, sediment time, type and concentration of the eluent, volume of sample, stability and reusability of adsorbent and effect of interfering ions on the quantitative recovery of the metal ions were checked and optimized. In the improved conditions, the limits of detection for Cr³⁺, Ag⁺, Co²⁺, Pb²⁺, Zn²⁺, and Cu²⁺ metal ions were 7.4, 4.1, 3.7, 7.0, 1.2 and 7.0 μg L^-1, respectively. The enrichment factor of proposed method for the target metal ions obtained in the range 111–125 and the relative standard deviations (RSD, C= 0.02 mg L-1, n= 3) were lower than 5.0%. Accuracy of the method was evaluated by recovery measurements on the spiked samples, and the recoveries achieved in the range of 91 to 106%.

Keywords: Heavy metal ions, magnetic nanoparticles, flame atomic spectrometry, solid phase extraction, water sample.

Graphical Abstract