A solvent system for delipidation of plasma or serum without protein precipitation

A technique has been developed which attains in 30 minutes complete removal of triglyceride, cholesterol, phospholipid, and unesterified fatty acids from plasma without protein denaturation. Plasma is agitated at room temperature with a mixture of butanol and di-isopropyl either in a 40:60 (v/v) ratio. The plasma proteins, including the apolipoproteins, remain in solution in the aqueous phase, while the organic phase contains the dissolved lipids. The phases can easily be separated by low speed centrifugation. Different lipids are simultaneously extracted, but the rate of extraction is most rapid for unesterified fatty acids, followed by triglyceride, cholesterol, and phospholipid at, respectively, decreasing rates. Selective extraction of unesterified fatty acids, triglyceride and total cholesterol can be achieved by di-isopropyl ether alone. Ionic strength and pH are not altered by these procedures.