To detect the volatile components in Modified Xiaoyao Pills by gas chromatography mass spectrometry.Methods:The volatile components in the solution of Modified Xiaoyao Pills were extracted by steam distillation.N-octadecane was used as internal standard substance for reference.Through the design of the orthogonal experiment,it was found that when the extraction time was 9 hours,the solid-liquid ratio was 1:15,and the soaking time was 10 hours,it was the best time to extract the volatile components in Modified Xiaoyao Pills by water distillation.The gas chromatography-mass spectrum and the specific chemical components of volatile components in Modified Xiaoyao Pills were analyzed.The chromatography condition of GC-MS chromatogram mass spectrometric study:the Rxi-5ms chromatographic column (30 m×0.25 mm) was selected,the column flow rate was 1 mL/min; the flow ratio of helium gas (He) was used as the carrier gas,and the flow ratio of 30:1 was adopted; the sample volume was 0.5 μL,the inlet temperature was 260 ℃.The temperature rising procedure started.First the temperature of the initial column temperature was 60 ℃ for 3 minutes,the temperature rose to 175 ℃ by the heating rate of 10 ℃/min,and decreased by 10 times at the rate of 1 ℃/min to 195 ℃,and at last increased the heating rate 5 times to 240 ℃ at the rate of 5 ℃/min,and then slowly increased to 250 ℃ after 15 minutes,and the delay time of solvent was 3 minutes.Mass spectrum condition:the bombardment energy of the electronic bombardment ion source was set to 70eV,the temperature of the ion source was set to 200 c,and the voltage was detected by 0.7 KV; the scanning range of the total spectrum was m/z40-550amu.Results:The accuracy,repeatability and stability of the GC-MS method were good.In the GC-MS study,N-octadecane (S) was used as the internal standard substance in Modified Xiaoyao Pills to detect the volatile components in 53.By comparing the chromatographic peaks detected in the total ion flow chromatogram with the standard spectra of NIST standard mass spectrometry database,the specific chemical composition information of the 53 volatile components was analyzed,including 11 aromatic and terpene volatile components,8 species of terpene alcohols and 6 kinds of aldehydes.Conclusion:Gas chromatography-mass spectrometry (GC-MS) is used to study the volatile substances in Modified Xiaoyao Pills,and to analyze its specific chemical composition and provide the basis for the quality control of Modified Xiaoyao Pills.