Determination of mineral oil in food packaging paper by solid phase extraction- gas chromatographyflame ionization detector

The solid phase extraction- gas chromatography flame ionizationdetector was developed for determination of mineral oil in food packaging paper. N- hexane / ethanol( 1 ∶ 1,v / v) as the extraction solvent,the immersion,ultrasonic and microwave assisted extraction method were compared and optimized. Extract was purified by silver nitrate silica gel column; mineral oil of food materials was determinated with GC- FID.The results showed that the optimum for ultrasonic extraction: extraction time 20 min,temperature 30 ℃,extraction times 2 and solid to liquid ratio 1∶10.The calibration curve of paraffin oil was linear in the range of 20~500 mg / Lwith correlation coefficient 0.9996.Thelimit of detection and the limit of quantitation were 2.57 mg / L and 7.79 mg / L,respectively.And therecoverieswere between 79.0% and 86.5%,with relative standard deviation( RSD) less than 5.0%,the RSD of intra- day and inter- day were less than 3.0%.Finally,the method was applied in the determination of mineral oil in six kinds of food packaging paper,it revealed that mineral oil of food packaging paper used in biscuits was the highest; the content of mineral oil was between 160.8 and 6104.9 mg / kg. The method was sensitive,accuracy andrapid,which was suitable for determining mineral oil in food packaging paper.