The Portable GC-MS and HS/SPME-GC×GC-TOF MS-Based Analysis of the Difference of Citri Grandis Exocarpium from Different Regions

Abstract In this study, the portable GC-MS and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF MS) combined with headspace solid-phase microextraction (HS/SPME) combined with chemometric were firstly used to analyze the volatile components of Citri Grandis Exocarpium that were from Huazhou (CGEH) and Guangxi (CGEG), respectively. The results from portable GC-MS only can identified some differences between samples. Compared with results from HS/SPME-GC×GC-TOF MS we found that portable GC-MS could not analyze the mark of CGEH.From identification of GC×GC-TOF MS we got that total 304 chemicals among which 261 were firstly reported were identified. Among them 52 compounds were only detected in CGEH, 81 were unique in CGEG and 171 were in both CGEH and CGEG. The volatile components in CGEH were classified into 17 and CGEG into 19 types. The contents of alkene aromatics, hydrocarbons and alcohols in both CGEH and CGEG were relatively high. These results fully demonstrated the detection ability of GC×GC-TOF MS. Principal Component Analysis (PCA) and Orthogonal Partial Least Squares (OPLS-DA) were performed. The results indicated that there was basically no difference from different batches of the same origin. However, there were obvious differences between CGEH and CGEG. 10 compounds in CGEH were screened out the values of |p(corr)|>0.9, |p|>0.06 and VIP value > 1.1. These results proved portable GC-MS could not find marks of Citri Grandis Exocarpium and GC×GC-TOF MS could find it.