Study On The Separation Of EPA And DHA By Prepareted Metal Ions Modified Silica Gel

EPA and DHA,which are the characteristic PUFA compounds of fish oil,with significant bioactivities,have been widely used in the development of new drugs and health foods.The traditional separation methods are unable to effectively separate EPA and DHA,so the combination of several ways is necessary.The combined with column chromatography is the most effective among them.However,most of the existing column chromatography use the physical conbination to connect Ag+to the surface of a silica gel.Ag+has the poor stability,easy to fall off,and causes the polution of samples.Based on the column chromatography to separate EPA and DHA,Ag+,Cu+,and Cu2+modified silica gel was screened by the separating degree of EPA and DHA,eventually found the modified silica gel,which separated EPA and DHA effectively,and summarized the corresponding chromatogeaphic regulation that provided the technical guidance for the furture industrialized production.The main contents of this research were divided into three parts:1.On the analyze columns using the Ag+,Cu+,and Cu3+ modifled silica gel as immobile phases(4.6×250 mm),the separation effect of EPA and DHA was evaluated by the degree of separation.The result indicated that after taking y-chloropropyltrichlorosilane as the medium and connecting ethylenediamine to the surface of silica gel,finally,the synthesized Ethylenediamine-grafted silica gel(EDA/SiO2,amino silica gel,grain diameter:10?40?m)was obtained.When the sample size was 5 ?g,flow velocity was 1mL/min,and mobile phase was hexane:isobutanol=1000:1,EPA and DHA could be separated effectively and the separation degree was 1.44.2.This research was about the adsorption of Ag+cations on EDA/SiO2,and the optimized condition of separation of EPA and DHA by EDA/SiO2.The result indicated that Ag+ modifned amino silica gel was the stablest when the quality ratio was EDA/SiO2:AgNO315:1,pH was 6,and the reaction time was 25 h.Meanwhile,the baseline separation was achieved,and the separation degree was 1.50 in the case that mobile phase hexane:isopropanol=1500:1,flow velocity was 1mL/min,sample concentration was the mixture of 1mg/mL of EPA and DHA,sample size was 5?L.3.On the analyze column which was manufactured by using commercially available universal amino silica gel as immobile phase,the retention behavior of EPA and DHA was estimated in normal phase system,meanwhile,the impact of grain diameter and mobile phase of amino silica gel modified by Ag+on the separation of EPA and DHA was inspected.The result indicated that the separating degree of 5 ?m amino silicone silver was 1.87,which was better than 0.80 of 10 ?m.And the separation degree of EPA and DHA increased as the hexane proportion in mobile phase increased.When the mobile phase was hexane:isobutanol=2000:1,the sample size was 5 pg,the separation of EPA and DHA was 2.03,which turned out to be the best effect.