Glycerin Extraction Combined with High Performance Liquid Chromatography-Tandem Mass Spectrometry for Determining the Contents of Seven Types of Chemical Components in Tea and Its By-Products

In this study, glycerin was used instead of traditional solvents such as methanol in combination with ultrasonic treatment for the high-efficiency extraction of multiple chemical components from tea. Furthermore, a quantitative analytical method for 130 chemical components belonging to seven classes in tea and its by-products was developed using ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-QQQ-MS/MS). The results showed that the extraction efficiency of glycerol was comparable to that of methanol and ethanol, and significantly better than that of water. The developed method had high sensitivity (limit of detection of 0.0001-4.3321 mg/kg) and accuracy (recoveries of 80.10%–121.12%). Appling this method to real samples, the content of each component varied greatly among different types of tea and by-products. Compared with tea samples, tea residue, a tea by-product, contained higher contents of caffeine, catechin and theanine, indicating the potential value of this by-product.