Biological sample pretreatment method and free amino acid detection method

The invention belongs to the technical field of analysis and detection, and particularly relates to a pretreatment method of a biological sample and a detection method of free amino acid. The method comprises the following steps: carrying out protein precipitation on serum or urine by using a 5-sulfosalicylic acid aqueous solution, carrying out mixed incubation on excrement and PBS (Phosphate Buffer Solution), carrying out centrifugal separation, and carrying out centrifugal separation by using a Milipore-Ultra free filter to obtain a to-be-detected sample solution. The pretreatment method provided by the invention does not need derivatization treatment, improves the extraction and separation effect of free amino acids in a biological sample and the accuracy of qualitative and quantitative detection results, and has universality for various chiral amino acids. Moreover, the pretreatment method provided by the invention does not need derivatization treatment, and is simple to operate, short in pretreatment tim