Analysis Methods For The Determination Of Mineral Oil Contaminants In Foods With Different Fat Content

An anlysis method for the determination of mineral oil saturated hydrocarbons(MOSH)and mineral oil aromatic hydrocarbon(MOAH)in commercial processed food products,edible oil and chocolate was proposed based on on-line liquid chromatography-gas chromatography-flame ionization detection(HPLC-GC-FID).This paper also studied the relationship between storage time and mineral oil content,developed a method for rapid screening of low fat samples by three-dimensional fluorescence spectroscopy and optimized the epoxidation method of chocolate samples.The obtained results are as follows:(1)MOAH in aromatic hydrocarbon monomers,industrial oils and 48 processed food products was determined by three-dimensional fluorescence spectroscopy.The number and intensity of fluorescent peak increased as benzene ring's number increases and the location of fluorescent peak tended to red-shift.HJ oil was selected as a reference material for the calibration,the fluorescence intensity at EX230 nm/EM330 nm was selected to determine MOAH in grain samples.The detection results of fluorescence spectroscopy and LC-GC methods were highly correlated(r=0.946).(2)MOSH and MOAH in 56 rice samples were determined by the established method,9 samples were not detected MOSH and 17 samples had MOAH.The level of pollution in the rice was lower,the mineral oil content in rice from different sources was also different.The experiment also found that as the storage time increase,the mineral oil pollution content will also increase.(3)MOSH and MOAH in 46 edible oil and 28 chocolate samples were determined by the established method.More than half of the edible oil samples were highly contaminated with mineral oil.The extracting,enriching and epoxidation which was used to remove olefin from chocolate conditions were optimized,and a method for the accurate determination of MOSH and MOAH in chocolate was proposed.It was found that MOSH contamination in chocolate products in China was common and there was no obvious relationship between packaging materials,fat content and pollution content,but correlationship between processing technology and contaminant content was found.