3. Results and discussion3.1. Extraction and delipidationThe analysis of PAs in food samples is complicated becauseof their very low concentrations and the high matrix effects ofhigh lipid foodstuffs. Thus, it is important to selectively extractthe PA contents and effectively eliminate the lipid contents priorto instrumental analysis. In this study, methanol was used as theultrasonic extraction solvent for PAs from food matrices with var-ious properties because methanol has shown a good solubility forPAs. However, to determine the PAs in aqueous samples such asmilk, chloroform-methanol (1:1, v/v) was selected to clearly sep-arate the two phases [23–26]. Using both solvents, the overallextraction yield of PAs was above 80%, giving acceptable valuesfor all of the PAs. Moreover, the sonication method is rapid, simple,and amenable to simultaneous PA extraction in a relatively shorttime.