Geographical Discrimination of Xinhui Citri Reticulatae Pericarpium by DART-QTOF-MS

Xinhui Citri Reticulatae Pericarpium (CRP, "Chenpi") is highly valued but is frequently challenged by origin-related adulteration and mislabeling. In this study, a rapid fingerprinting strategy based on direct analysis in real-time quadrupole time-of-flight mass spectrometry (DART-QTOF-MS) coupled with chemometric analysis was developed for the geographical characterization of CRP. DART-QTOF-MS enabled fast acquisition of mass spectral fingerprints with minimal sample preparation, and characteristic compounds were tentatively assigned on the basis of accurate mass and library matching. Comparative analysis showed that the high-mass region was dominated by polymethoxylated flavones and exhibited relatively limited between-region variation. In contrast, the low-mass region contained more evident origin-related differences and provided more informative variables for classification. Among the low-molecular-weight compounds, methyl N-methylanthranilate was markedly enriched in Xinhui samples, and 2-indolinone was identified as a promising candidate marker and further confirmed in CRP extracts by UPLC-MS/MS. OPLS-DA based on selected low-molecular-weight markers supported the discrimination of core Xinhui CRP and non-core Xinhui CRP. Overall, these results demonstrate the potential of DART-QTOF-MS as a screening tool for CRP origin authentication and highlight the value of low-molecular-weight markers for future quality-control applications.