A liquid chromatographic differential refractive index detector (RI) and an ultraviolet absorption (at 195 nm) detector (UV) were studied for detection of triglyceride (TG) and phospholipid (PL) molecular species. It was found that the log UV/RI detector response ratio was linearly related to the log of the number of conjugated double bonds (degree of unsaturation) of the lipid in a predictable fashion, indicating the usefulness of the combination of both detectors in TG and PL analysis. The detection limit of the RI detector for TG and PL was found to be 5 × 10−7M or as sensitive as the UV detector for saturated TG and PL.