A newly synthesized graft copolymer for magnetic solid phase microextraction of total selenium and its electrothermal atomic absorption spectrometric determination in food and water samples.

A newly synthesized polystyrene-g-polyoleic acid-g-polyethylene glycol graft copolymer (PoleS-PEG) was used as adsorbent in the solid phase microextraction of selenium ions by using electrothermal atomic absorption spectrometry (ETAAS). Neodymium magnet was used for separation of analyte ions. Various analytical parameters such as pH, adsorbent amount, mixing time, eluent solution, sample volume, etc. were optimized. The matrix effects of some cations and anions were also studied. The capacity of the adsorbent was found 11.5 mg g-1. The preconcentration factor was found to be 50. The detection limit (LOD) and quantification limit (LOQ) were found 6.06 ng L-1 and 20 ng L-1, respectively. The calibration curve was linear in the range of 0.02-4.0 μg L-1. Relative standard deviation was found 3.2%. The accuracy of the method was provided by using standard reference materials. The optimized method was successfully applied to natural water and food samples.