Simplified measurement of monoglycerides, diglycerides, triglycerides, and free fatty acids in biological samples.

IPublished methods for the determination of plasma triglycerides are of two kinds, enzymatic (1-3) and colorimetric (4-7). Both require preliminary removal of phospholipids and saponification of triglycerides. With the enzymatic method, glycerin released is quantitatively determined with the specific enzyme GPDH’ and NAD. In the colorimetric methods, glycerin is oxidized to formaldehyde with periodic acid. The formaldehyde is then reacted to form a chromotrope with chromotropic acid (4, 5, 7) or acetylacetone (6). FFA are extracted from the plasma and determined acidimetrically as described by Dole (8) and others (9-11). The colorimetric determination of plasma FFA as described by Duncombe (12) is not an alternative procedure to the Dole method, since, as Duncombe himself admits, phospholipids interfere with this determination. Measurement in plasma of both triglycerides and FFA requires a long and laborious standardization procedure to obtain good reproducibility. Further difilculties are encountered when attempts are made to determine glycerides and FFA quantitatively in liver-problems mainly resulting from the presence of monoglycerides and diglycerides