Hg²⁺ion-imprinted polymers sorbents based on dithizone–Hg²⁺chelation for mercury speciation analysis in environmental and biological samples

Abstract

For mercury speciation analysis in environmental and biological samples, novel Hg 2+ ion-imprinted polymers (IIPs) were synthesized by a sol-gel process using the chelating agent dithizone, and then dithizone-Hg 2+ chelate as a template and 3-aminopropyltriethoxysilane as a functional monomer, followed by solid-phase extraction (SPE) and atomic fluorescence spectroscopy (AFS) detection. The resultant Hg-IIPs offered high binding capacity, fast kinetics, and their adsorption processes followed aLangmuir isotherm and pseudo-second-order kinetic models. The IIPs displayed excellent selectivity . Furthermore, the analytical results for the spiked mercury species in real biological samples, such as human hair and fish meat, confirmed that the methods are practically applicable to speciation analysis. The IIPs-SPE-AFS demonstrated significant application perspectives for rapid and high-effective cleanup, enrichment and determination of trace mercury species in complicated matrices.

Molecular imprinting: perspectives and applications

“…However, low selectivity is often obtained when the metal ion itself acts as an imprinting template, since the metal ions have the same charges, similar ionic radii and properties. 34 Now, the method of using a metal ion and a ligand complex as the actual imprinting template is a new trend in ion-imprinting. The metal ion and ligand complex can easily pre-polymerize with functional monomers, and after the polymerization reaction, the metal ion is removed by elution, leaving specific recognition sites for the metal ion, which contributes to the high adsorption efficiency and selectivity for metal ions.…”

“…The metal ion and ligand complex can easily pre-polymerize with functional monomers, and after the polymerization reaction, the metal ion is removed by elution, leaving specific recognition sites for the metal ion, which contributes to the high adsorption efficiency and selectivity for metal ions. For example, Chen et al 34 synthesized novel Hg 2+ IIPs by a sol-gel process using the chelating agent dithizone, with the dithizone-Hg 2+ chelate as a template and 3-aminopropyltriethoxysilane as a functional monomer. The resultant Hg-IIPs displayed excellent selectivity toward Hg 2+ over its organic forms and other metal ions.…”

Current status and challenges of ion imprinting

“…A kind of nanoparticle 144 for mercury speciation in surface waters was synthesized and used for SPE and limits of quantication were achieved, namely 0.015 mg L À1 for Hg(II) and 0.02 mg L À1 for methylmercury. In 2014, 147 we further presented speciation analysis of Hg by using dithizone-Hg(II) chelate as a template for Hg(II)-IIPs synthesis, as schematically shown in Fig. 10A, followed by SPE and atomic uorescence spectroscopy (AFS) detection in environmental and biological samples.…”

Synthesis of multi-ion imprinted polymers based on dithizone chelation for simultaneous removal of Hg2+, Cd2+, Ni2+ and Cu2+ from aqueous solutions

“…9,20 In addition, sol-gel process may make the contributions to high yield, because it is a more mature method without needless ingredients.…”

“…9,12,[21][22][23][24][25] The traditional view expects a tautomeric equilibrium for dissolved dithizone between the ketone form (Ph-NH-NH]CS-N]N-Ph) and the enol form (Ph-NH-N]C(SH)-N]N-Ph). As pH increases, it is easy for S with a lone-pair electron to bind with H to form a thiol group, which would easily form a complex with metal ions.…”