Abstract: The volatile components of cassia twig, white peony, and their drug pairs were analyzed using headspace solid-phase microextraction（HS-SPME） combined with gas chromatography-mass spectrometry（GC-MS）（HS-SPME-GC-MS）. The optimal extraction conditions were investigated using single factor analysis. The relative content of each component was calculated using the area normalization method, and principal component analysis （PCA） was performed. The results showed that the optimal extraction conditions were the sample size of 0.60 g, extraction temperature of 60 ℃, extraction time of 15 min, and analysis time of 3 min. Cassia twig, white peony, and their drug pairs identified 47, 49, and 54 components, and the relative contents were 96.91%, 90.58%, and 94.57%, respectively. Principal component analysis showed significant differences in the comprehensive scores of cassia twig, white peony, and their drug pairs, with cassia twig and white peony drug pair having the highest comprehensive score. The volatile components in the cassia twig and white peony drug pair mainly came from cassia twig. The volatile components after the combination of cassia twig and white peony were significantly different from those in a single drug, and there was a significant change in relative content.

Key words: cassia twig, white peony, cassia twig and white peony drug pair, volatile components, headspace solid-phase microextraction, gas chromatography-mass spectrometry, HS-SPME-GC-MS