QUANTITATIVE DETERMINATION OF ARACHIDONIC ACID AND DOCOSAHEXAENOIC ACID IN YOLK PHOSPHOLIPID OF HEN EGG BY GC/MS INTEKNAL.STANDARD METHOD

The fatty acid(FA)compositions of yolk phospholipid(PL)obtained by supercritical fluid CO₂ extraction(SFE-CO₂)were analyzed by GC/MS.The method of internal standardquantitation of arachidonic acid(AA,C_20:4) and docosahexaenoic acid(DHA,C_22:6)in yolk PLwas established. It includes the following steps:SFE-CO₂ extraction of fresh egg yolk powder to getyolk PL; methylation of FAs in yolk PL and checking the esterification degree with TLC;theidentification of FA compositions in the yolk PL by G C/MS,including the matching of their massspectra with NIST library and of retention times with twelve FA methyl ester standards;the making-up of standard curve using internal standards of C_20:0 and C_24:1.A linear relationship was obtainedin the concentration rage of 25～150 ng·μl^-1 and the correlation coefficients(Y)of AA and DHAwere 6.9982 and 0.9983 respectively.The contents of AA and DHA were 6.72%and 2.25%respectively.