A direct colorimetric method for the determination of phospholipids with dithiocyanatoiron reagent

A simple and sensitive colorimetric method for the quantitative determination of phospholipids in various kinds of biological materials is described. The method, modification of a previous method using tetrathiocyanatocobaltate, is based on the formation of hydrophobic complexes between dithiocyanatoiron reagent and phospholipids. Under the standard conditions all species of neutral phospholipids, including lysophosphatidylcholine and sphingomyelin, form stable hydrophobic complexes with the iron compound. Although species of acidic phospholipids also have slight affinity for the iron compound, they do not disturb the assay appreciably, because their contents in biological materials are low. Under special conditions, the iron compound reacts only with phosphatidylcholine, and therefore it may also be used for specific determination of this phospholipid.