A convenient method for determination of the C20-22 PUFA composition of glycerolipids in blood and breast milk.

A convenient method was developed for preparation of FAME in small amounts from glycerolipids of blood or breast milk. Initially, 0.04-0.06 mL blood or breast milk was spotted onto a small piece of filter paper (1.5 x 1.5 cm) that had been washed with acetone containing 0.05% 2,6-di-tert-butyl-p-cresol (BHT). Each piece, once it had dried, was put in a small test tube, to which 2 mL hexane and 0.2 mL 2 M KOH/methanol were added. After vigorous mixing or sonication for 2 min at room temperature, the solution was neutralized or acidified by the addition of a few drops of acetic acid. To the solution was added 2 mL H2O, and then the hexane layer that separated was concentrated to dryness in vacuo. The FAME obtained were analyzed by GC. The method was applicable to the analysis of a large number of blood and breast milk samples, and the arachidonate/(eicosapentaenoate + docosahexaenoate) ratios could be determined rapidly.