QUANTITATIVE DETERMINATION METHOD FOR TRACE PROTEIN IN LIPID

PURPOSE:To quantitatively determine the trace protein in lipid with high sensitivity by dissolving the lipid in an organic solvent, reacting it with an acid solution, removing the lipid, binding a coloring matter, and measuring the absorbance. CONSTITUTION:A trichloroacetic acid aqueous solution is added to and reacted with a sample solution dissolving egg yolk phosphatidylcholine which is a phosphorus lipid, in ethanol, for example, the mixture is homogenized in ethanol, it is sucked and filtered with the filter paper for a quantitative analysis, and protein is adsorbed on the filter paper. Hot ethanol, ethanol/ether mixed liquid, chloroform, and ether are combined and sucked, the filter paper is washed and dried, it is dyed with a dyeing liquid dissolving Coomassie brilliant blue G-250 in acetic acid, and the extra dyeing liquid stuck to the filter paper is removed. The filter paper is dried, then a fixed quantity of a pigment releasing agent is added to release the coloring matter, the concentration of the released coloring matter is measured as absorbance, and the protein concentration in the sample is calculated based on the calibration curve of the standard protein.