| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1251813 | Chemistry and Physics of Lipids | 2012 | 7 Pages |
Accurate determination of lipid concentrations is an obligatory routine in a research laboratory engaged in studies using this class of biomaterials. For phospholipids, this is frequently accomplished using the phosphate assay (Bartlett, G.R. Phosphorus Assay in Column Chromatography. J. Biol. Chem. 234, 466–468, 1959). Given the purity of the currently commercially available synthetic and isolated natural lipids, we have observed that determination of the dry weight of lipid stock solutions provides the fastest, most accurate, and generic method to assay their concentrations. The protocol described here takes advantage of the high resolution and accuracy obtained by modern weighing technology. We assayed by this technique the concentrations of a number of phosphatidylcholine samples, with different degrees of acyl chain saturation and length, and in different organic solvents. The results were compared with those from Bartlett assay, 31P NMR, and Langmuir compression isotherms. The data obtained show that the gravimetric assay yields lipid concentrations with a resolution similar or better than obtained by the other techniques.
► A detailed procedure for the gravimetric analysis of the concentrations of lipid stock solutions is presented. ► The concentrations of a number of phosphatidylcholine samples in different organic solvents have been assayed by different techniques. ► The determination of the dry weight of lipid provides the fastest, most accurate and generic method to assay lipid concentrations.
