Analysis of fingerprint differences in volatile substances in leaves of different walnut varieties by GC-IMS

Abstract:【Objective】To explore the volatile organic characteristics of different walnut varieties, the experiment was undertaken to compare the differences among the walnut leaves, and construct a vola- tile organic odor fingerprint pattern for different kinds of walnut leaves.【Methods】Gas chromatogra- phy Mobility Technology (Gas chromatography Mobility Spectrometrygc- IMS) was used to analyze Black walnut of the eastern United States, American Bill black walnut, Wen 185, Xinxin 2, leatheroid walnut, American Red walnut, Zijin walnut and Carya, etc. Eight walnut leaf odor fingerprints, using the main component analysis method (PCA), were systematically analyzed based on the three-dimen- sional and two-dimensional map of the walnut leaves, and the volatiles (Volatile Organic Compounds, VOCS) odor fingerprint pattern differences were compared. Gas chromatography- Ionmobility Spec- trometrygc- IMS is a detection technology that combines both gas chromatography and ion migration spectra. This detection technique overcomes the limitations of ion migration spectrum technology sepa- ration degree, so that ion migration spectral signal response after the quality of the gas phase pre-separa- tion is significantly improved, and the ion migration spectrum is further enriched by the drift time infor- mation, which makes the chemical information obtained after the gas chromatography is more abun- dant. Ion migration spectrum (IMS) has recently been an effective analytical testing tool, with high sen- sitivity, rapid response, easy operation, etc., attracting extensive attention to researchers in different fields. IMS can detect multi-compound compounds, including alcohols, aldehydes, aromatic, amines, es- ters, ketones, etc., typically in combination with other detection methods, like gas chromatography or mass spectrometry. It not only increases the selectivity of IMS, but also make up for the shortcomings of poor IMS separation. In the IMS field, gas chromatography-ion migration spectrum (Gas chromatog- raphy Mobility Spectrometry GC-IMS) is the most commonly used technique. It has applications in drug monitoring, hazardous chemical testing, respiratory analysis, biological analysis, and food testing. GC-IMS is widely used in the food sector. It can achieve research on food traceability, authenticity, quality grading, and flavor consistency. And it can also be applied in the trace analysis of the drug resi- due, classifying food level and origin and test food adulteration fake. GC-IMS has multiple advantages compared to traditional analytical techniques, and the application is increasing.【Results】The volatile organic compounds contained in eight varieties of walnut leaves mainly included substances such as ter- pene, esters, aldehydes, alcohols, and small ketones. Volatile organic matter in different genus and dif- ferent kinds of walnut leaves was very large, Wen 185, Xinxin 2, leatheroid walnut, Zijin walnut, Ameri- can Red walnut were relatively close, belonged to the pecan; Black walnut of the eastern United States and American Bill black walnuts as black walnut variety resources belonged to the walnut; Carya were the pecans and other walnut leaves. The contents of Metolane and β-stone benne ether in the walnut were much higher than the other walnut leaves; the content of isoamate in the Xinxin 2 was much high- er than the other walnut leaves; the group was married in the American Red walnut. The content of wal- nut leaves was much higher than other walnut leaves, which can be used in the district Wen 185, Xinxin 2, leatheroid walnut and American Red Walnut; two of the volatile organics were found in black walnut leaves, but hepthal was in the black walnut in the United States. The content in the black walnut of east- ern United States leaves was much higher than that in the American Bill black walnut nuclear leaf blan- ket; two American black walnut leaves can be distinguished from the two US black walnut leaves. The content of propanol in the Carya blades was much higher than that in others.【Conclusion】American Bill black walnut, Wen 185, Xinxin 2, leatheroid walnut, American Red walnut, Zijin walnut and Carya were all pecans, but their 8 volatile organic matters referred to different fingerprints. The difference in the pattern was obvious. Through PCA and fingerprint analysis, it was very good to distinguish among eight different varieties of walnuts. The later studies should also choose Black walnut of the eastern United States, American Bill black walnut, Wen 185, Xinxin 2, leatheroid walnut, American Red Wal- nut, Zijin walnut, Carya, etc. Eight walnut leaves samples, using gas chromatography-ion Mobilized spectrum (GC-IMS) technology, were studied to determine different kinds of volatile organic smell of volatile organic matter released during different growth periods, and the three-dimensional and two-di- mensional map and PCA analysis of the walnut leaves were systematically analyzed, by comparing the main components of volatile organics at different periods, the difference in the relative content, the ef- fective utilization of walnut leaf volatile organic matter and the late extraction of the volatile organic substance in the walnut blade, which was a walnut blade resource. Experiments showed that the walnut leaf extract has developed a new type of pollution-free plant growth regulator and seed germination ac- celerator, which is used in agricultural production and aerial sowing afforestation. Walnut extracts have anti-parasforma and aversion, and gas chromatography-ion mobility spectrum (GC-IMS) technology can be used to rapidly identify and extract volatile organics as a mosquito repellent, and of course, this is also a valuable resource.