Magnetic effervescent tablet-assisted ionic liquid dispersive liquid–liquid microextraction of selenium for speciation in foods and beverages

ABSTRACT

A novel, simple and rapid method based on magnetic effervescent tablet-assisted ionic liquid dispersive liquid–liquid microextraction (MEA-IL-DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) determination was established for the speciation of selenium in various food and beverage samples. In the procedure, a special magnetic effervescent tablet containing CO₂ sources (sodium carbonate and sodium dihydrogenphosphate), ionic liquids and Fe₃O₄ magnetic nanoparticles (MNPs) was used to combine extractant dispersion and magnetic recovery procedures into a single step. The parameters influencing the microextraction efficiency, such as pH of the sample solution, volume of ionic liquid, amount of MNPs, concentration of the chelating agent, salt effect and matrix effect were investigated and optimised. Under the optimised conditions, the limits of detection (LODs) for Se(IV) were 0.021 μg l^–1 and the linear dynamic range was 0.05–5.0 μg l^–1. The relative standard deviation for seven replicate measurements of 1.0 μg l^–1 of Se(IV) was 2.9%. The accuracy of the developed method was evaluated by analysis of the standard reference materials (GBW10016 tea, GBW10017 milk powder, GBW10043 Liaoning rice, GBW10046 Henan wheat, GBW10048 celery). The proposed method was successfully applied to food and beverage samples including black tea, milk powder, mushroom, soybean, bamboo shoots, energy drink, bottled water, carbonated drink and mineral water for the speciation of Se(IV) and Se(VI) with satisfactory relative recoveries (92.0–108.1%).

KEYWORDS:

• Ionic liquid-dispersive liquid–liquid microextraction
• graphite furnace atomic absorption spectrometry
• effervescent
• selenium speciation
• food

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Key Project of Research and Development Program of Zhejiang Province [grant number 2015C03G2610002]; and the National University Students’ Innovation and Entrepreneurship Training Program [grant number 201511481009].