Magnetite β-lactoglobulin@Fe₃O₄ nanocomposite for the extraction and preconcentration of As(III) species

Speciation and accurate determination of class I carcinogen As(III) species from complex samples remains challenging either due to lack of selectivity and/or ultra-low analyte concentration or matrix interference. Sample preparation via preconcentration increases the analyte concentration far above the instrumental detection limit, and simultaneously clean up the sample for accurate analysis. Herein, we report a new nano-sorbent consisting of a magnetite Fe₃O₄ core coated with β-lactoglobulin (β-lg) shell. The prepared Fe₃O₄@β-lg sorbent are of uniform size with an average diameter of 1 µm. The Fe₃O₄@β-lg nanocomposite selectively binds As(III) over As(V) ions at wider pH range. Experiments were conducted to optimize the sample pH, column flow rate, preconcentration factor and suitable eluent to recover the sorbed analyte ions. The technique was effectively used to evaluate the As(III) species in ecological water samples. The detection limits (3σ/m) of the proposed method was found to be 0.98 ng L⁻¹. The recovery of the spiked amount following the optimized procedure was ranges from 97.0 to 100%.