Polyelectrolyte multilayers on magnetic silica as a new sorbent for the separation of trace copper in food samples and determination by flame atomic absorption spectrometry

• Assembling polyelectrolyte multilayers (PEMs) on the surface of magnetic silica.
• Fast adsorption kinetics, high selectivity, and high adsorption capacity.
• Simple, quick and selective method for Cu2+ extraction and determination.

A novel magnetic silica sorbent with polyelectrolyte multilayers (PEMs) on its surface was prepared, and the sorbent was used for the magnetic solid phase extraction (MSPE) of trace Cu2+ in drinking water with flame atomic absorption spectrometry (FAAS) as the detector. The experimental parameters for the MSPE procedure, such as the pH, desorption conditions, ultrasonic time and co-existing ions effects, were investigated. The adsorption capacity of the new sorbent was 14.7 mg g−1 for Cu2+. The detection limit of the developed method was 0.23 ng mL−1 for Cu2+ with an enrichment factor of 95.7. The analytical data obtained from the certified reference water and rice samples were in good agreement with the certified values. This method was also successfully applied to the determination of trace Cu2+ in different food samples with satisfactory results.

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