LC/MS/MS Quantitation of Eicosapentaenoic Acid in Rat Plasma

Since EPA appears in many different forms, it will need to be released from conjugated forms by hydrolysis in order to quantitate total EPA in plasma samples. Plasma samples were first incubated under acidic conditions (ACN/6N HCl) for 1 hour at 100C to release EPA, liquid-liquid extraction with hexanne followed to clean up the samples from the matrix. EPA-d5 was added as an internal standard before hydrolysis. Hexand supernatant was evaporated to dryness, reconstittued with ACN/water and injected into an LC/MS/MS using a Kinetex XB-C18 column with an ammonium acetate/ACN/H20 mobile phase. TSQ quantum instrument at negative mode was used for detection/quantitation.