The invention provides a method for detecting
oxalic acid in
urine by adopting an HPLC-ESI-MS / MS. The method comprises the following steps: S1, taking a collected sample, adding
oxalic acid-1, 2-13C as an
internal standard of
oxalic acid, mixing an
internal standard solution and the collected sample according to a ratio of 2: 1, performing vortex for 5 minutes, and performing
centrifugation for 5 minutes at 4000 rpm to obtain a
urine sample; s2, detecting the sample by using a liquid
chromatography tandem
mass spectrometer; s3, adopting stable
isotope labeled oxalic acid-1, 2-13C as an
internal standard of oxalic acid, preparing a series of standard substances with different concentrations, making a
standard curve, taking the concentration of an oxalic acid working
standard solution as an X axis, taking a
peak area ratio of the standard to the internal standard of a read result as a Y axis, carrying out
linear regression analysis, and obtaining a regression equation through '1 / x2' weight; and substituting the
area ratio of the oxalic acid in the sample to the internal standard peak into the
standard curve equation, and calculating the concentration of the oxalic acid in the
urine sample. According to the method,
derivatization,
solid-phase extraction, acidification and other operations are not needed, the analysis technology is greatly simplified, the detection time is shortened, and the
sample stability is improved.