Method for reducing content of nonvolatile buffer salts in LC-MS test substance

The invention relates to a method for reducing the content of nonvolatile buffer salts in an LC-MS test substance, and concretely relates to a method for reducing the content of nonvolatile buffer salts in a liquid chromatographic elution fraction in liquid chromatography-mass spectrometry test. The method comprises the following steps: 1, processing a detection substance to prepare a solution, injecting the solution into a liquid chromatograph, eluting, and collecting a target substance elution fraction to be detected through mass spectrometry from the above obtained liquid chromatographic eluate; 2, fully mixing the elution fraction with an assistant; 3, centrifuging or filtering the above obtained mixed solution to separate a suspension and a clear liquid, and taking the clear liquid; and optional 4, concentrating the clear liquid. The method can effectively reduce the content of the buffer salts in the high performance liquid chromatographic eluate in order to reduce loss of a mass spectrometer in the subsequent mass spectrometry determination process of the eulate. The method adopting a simple treatment technology realizes great reduction of the concentration of nonvolatile buffer salts in the LC elution fraction in the LC-MS without loss of the target substance.