METHOD FOR PRETREATMENT OF BIOLOGICAL SAMPLE

The present invention provides a method for pretreatment of a biological sample in order to measure a protein contained in the biological sample by liquid chromatography/mass spectrometry. The method includes the step of adding an acetic acid aqueous solution to the biological sample, so as to prepare a pretreatment sample containing an acetic acid at a concentration ranging from 20 to 50 weight percent, both inclusive. In the present invention, a target protein contained in a biological sample is less prone to be adsorbed to a sample container, thereby resulting in an increased sensitivity of measuring the protein in the biological sample by mass spectrometry. Further, reproducibility of results of the mass spectrometry is improved, and reliability is increased.