Rapid preparation of melamine based magnetic covalent triazine polymers for highly efficient extraction of copper(II), chromium(III) and lead(II) ions from environmental and biological samples

Abstract

In this work, melamine based magnetic covalent triazine polymers (MCTPs) was prepared by decoration of melamine based triazine polymers on the surface of magnetic Fe3O4@SiO2 nanoparticles. The polymer decoration is realized by nucleophilic substitution reaction between melamine (as functional monomer) and 1,4-dibromobutane (as crosslinking agent), which is simple, rapid and cost effective. The resultant MCTPs showed good affinity toward Cu2+, Cr3+ and Pb2+ with fast adsorption kinetic (7 min) and high adsorption capacities (38.3, 33.9 and 49.7 mg g−1 for Cu2+, Cr3+ and Pb2+, respectively). Besides, the prepared MCTPs can be reused after adsorption, desorption and regeneration steps, and the phase separation is highly efficient with the addition of an external magnet. Thus, MCTPs was employed as a magnetic solid-phase extraction (MSPE) sorbent for the extraction of trace Cu2+, Cr3+ and Pb2+ followed by graphite furnace atomic absorption spectrometry (GFAAS) determination. Then the extraction conditions of the above-mentioned MSPE-GFAAS method were optimized, including sample pH, extraction/elution time, sample volume, etc. Under the optimized conditions, the MCTPs based MSPE-GFAAS method exhibit the following merits: short extraction/elution time (10/3 min), high enrichment factor (125 folds) and low detection limit (2.9, 1.4 and 6.1 ng L-1 for Cu2+, Cr3+ and Pb2+, respectively). Finally, the proposed method was successfully employed for the determination of trace Cu2+, Cr3+ and Pb2+ in tap water, river water, lake water, human urine and human hair samples. The adequate recoveries of 85 ∼ 105% in spiked samples were achieved, suggesting the promising potential of MCTPs based MSPE-GFAAS method as an effective method for evaluating the environment and biological effect of metal ions.