Non-volatile metabolomic differentiation of geographical origin and quality grade in pre-Qingming Xihu Longjing green tea using in-source fragment ion-assisted annotation
Xihu Longjing green tea (XHLJT) faces challenges in origin and grade authentication due to mislabeling and limited chemical interpretability of sensory evaluation. Here, an enhanced untargeted metabolomics workflow integrating in-source fragment ion (ISFI) identification was developed to improve annotation reliability...