[Analysis of volatile organic compounds (VOCs) fingerprint of raw and honey-fried licorice based on headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS)].

Licorice is one of the most commonly used traditional Chinese medicine. In clinic, raw licorice and honey-fried licorice are used in medicines, with the main effects in clearing away heat and detoxifying, moistening lungs and removing phlegm. Honey-fried licorice has effects in nourishing the spleen and stomach and replenishing Qi and pulse. Because traditional Chinese medicine exerts the effects through multiple components and multiple targets, the index components used in the quality evaluation of licorice are often difficult to reflect their real quality. In addition, most of studies for the quality standards have shown that honey-fried licorice are the same as licorice, with a lack of quality evaluation standards that can demonstrate their processing characteristics. The quality of medicine is directly related to its clinical efficacy, so it is necessary to establish a more effective quality control method. Licorice has a beany smell, which is one of the main quality identification characteristics. In this study, by taking advantage of the odor characteristics, a headspace-gas chromatography-ion migration mass spectrometry technology was used to establish a quality evaluation method. A total of 76 volatile components were identified. Through the dynamic principal component analysis, 7 kinds of volatile substances in raw licorice and 13 kinds of volatile substances in honey-fried licorice were statistically obtained, and could be taken as index components for the quality evaluation of raw and honey-fried licorice, respectively. This study could help realize the combination and unification of modern detection and traditional quality evaluation methods, and make a more realistic evaluation for the quality of licorice.