RESUMO
An alternative method based on an off-line solid phase extraction ( SPE ) combined with programmable temperature vaporizer-based ( PTV) large volume injection-gas chromatography-flame ionization detection ( LVI-GC-FID ) was developed. The goal of this study was to determine mineral oil saturated hydrocarbons ( MOSH ) in camellia seed oils. The purification condition of SPE columns with silver impregnated the activated silica gel and activated aluminum oxide was optimized. The optimal SPE cartridge was loaded with 10 g of Ag-activated silica gel per 10 g of activated aluminum oxide. The PTV initial temperature was set at 75℃ for 1 min (split 200:1), and heated from 75℃ to 370℃ at 250℃/min. Then the diverter valve was closed for 1 min and opened again with the split flow ratio changing to 50:1 . The injection volume was 40μL. The calibration curve of paraffin oil was liner in the range of 5-500 mg/kg with correlation coefficient of 0. 998. The detection limit (LOD) and the quantification limit (LOQ) of paraffin oils in hexane were 0. 26 mg/kg and 0. 80 mg/kg, respectively. The recoveries from spiked oil samples were between 93 . 3% and 112 . 7%, with relative standard deviation ( RSD ) of 1 . 8%-5 . 2%, the RSD of intra-day and inter-day were less than 2 . 6% . This procedure was applied to analyze the MOSH in 11 commercial camellia seed oils and the contamination was found to range from 6. 8 mg/kg to 76. 7 mg/kg. The method is simple in operation with high sensitivity, good reproducibility and low cost, and suitable for determination of MOSH in vegetable oils.