Studies On The Analysis Method Of Carotenoids And Vitamin K In Food

Fat-soluble vitamins is an important part in vitamins and vital to human body health. At present, the source of vitamins for normal hunman body is diet, which includes natural food and vitamin fortified food. So it is very important and practical to determine the two types of food.In this paper, on the background of lack of analysis methods for fat-soluble vitamins in food, analysis metheds of fat-soluble vitamins in food, such as fruits, vegetables, and dairy products were investigated simultaneously and established by LC-DAD and LC-MS/MS.As fruits and vegetables contains many kinds of carotenes and most of them are isomers, the method of HPLC-DAD for simultaneous detection of five carotenoids in fruits and vegetables were studied and established. On the basis of existing method for detection of2-3carotenes in literature, the pretreatment device was improved and chromatographic conditions were optimized. Two pairs of isomers(lutein and zeaxanthin, a-carotene and β-carotene) are simultaneous separated successfully by this method and achieved a favourable separation degree.The pretreatment method of milk powder sample, as the most complicated sample in the enriched vitamins food, was discussed. On the basis of national standard method, antioxidant and extraction solvent conditions were optimized. The method of HPLC-DAD for simultaneous detection of three carotenoids in dairy products were studied and established. The spiked recoveries obtained by this optimized conditions ranged from75.2%to114%, and the relative standard deviation(RSD) of each spiked test were less than7.7%. There are two types of cis and trans isomers in synthetic vitamins K1, but cis-isomer have no biological activity. With complex ingredients in milk powder samples, the method of HPLC-MS/MS for simultaneous detection of cis and trans vitamin K1in dairy products were studied and established. The research shows that matrix effect could be almost overcome by isotope internal standard method. The recovery obtained by this optimized method ranged from81.7%to113.7%, and the relative standard deviation(RSD) were less than7.2%.Trans-vitamins K1exist in natural for the only structure, as chlorophyll and other fat soluble interference compositions are rich in fruits and vegetables, the pretreatment technology are established with Al2O3solid phase extraction column made by ourselves, which is effective to eliminate interfering substances in fruits and vegetables and received a good recovery and low detection limit. The method of isotope dilution electrospray tandem mass spectrometry for determination of vitamin K1in fruits and vegetables are established.The pretreatment and detection methods were applied to analyse fruits, vegetables and dairy products. The results show that some vitamins in food fall short of label. The task of detecting vitamins in food is necessary. Carotenoids and vitamin K1are rich in the fruits and vegetables, especially in green plants.