Simple and sensitive determination of vitamin A and E in the milk and egg yolk samples by using dispersive solid phase extraction with newly synthesized polymeric material

A simple and sensitive determination method for trace amounts of vitamins A and E has been developed based on dispersive solid phase extraction (DSPE) and HPLC-DAD analysis in this study. In the proposed method, the vitamin molecules were retained on a newly synthesized solid phase material consisting of tetracycline-grafted polyacrylamide polymer (PAA-T). The method was applied by the conventional batch method and desorption of retained vitamins from PAA-T surface were carried out with acetonitrile. Then, the samples were filtered through a 0.45 mu m filter, transferred to HPLC vials. The analysis of the samples was carried out using a C18 column at a flow rate of 1 mL min(-1) with isocratic elution consisting of methanol (30 %) and acetonitrile (70 %). For vitamin A (retinol) and vitamin E(alpha-tocopherol) respectively; determination wavelengths: 324 and 292 nm, linear ranges: 20-700 ng mL(-1) and 50-1800 ng mL(-1), limit of detections (LOD): 5.71 ng mL(-1) and 14.28 ng mL(-1), relative standard deviations(RSD) for 5 repetitive measurements: 3.25 % and 2.85 %. For application of the developed method, recovery experiments were carried out and quantitative values were obtained in milk and egg yolks.