Optimization of a static headspace GC-MS method and its application in metabolic fingerprinting of the leaf volatiles of 42 citrus cultivars

Abstract

Citrus leaves, which are a rich source of plant volatiles, have the beneficial attributes of rapid growth, large biomass, and availability throughout the year. Establishing the leaf volatile profiles of different citrus genotypes would make a valuable contribution to citrus species identification and chemotaxonomic studies. In this study, we developed an efficient and convenient static headspace (HS) sampling technique combined with gas chromatography-mass spectrometry (GC-MS) analysis and optimized the extraction conditions (a 15-min incubation at 100 ˚C without the addition of salt). Using a large set of 42 citrus cultivars, we validated the applicability of the optimized HS-GC-MS system in determining leaf volatile profiles. A total of 83 volatile metabolites, including monoterpene hydrocarbons, alcohols, sesquiterpene hydrocarbons, aldehydes, monoterpenoids, esters, and ketones were identified and quantified. Multivariate statistical analysis and hierarchical clustering revealed that mandarin (Citrus reticulata Blanco) and orange (Citrus sinensis L. Osbeck) groups exhibited notably differential volatile profiles, and that the mandarin group cultivars were characterized by the complex volatile profiles, thereby indicating the complex nature and diversity of these mandarin cultivars. We also identified those volatile compounds deemed to be the most useful in discriminating amongst citrus cultivars. This method developed in this study provides a rapid, simple, and reliable approach for the extraction and identification of citrus leaf volatile organic compound, and based on this methodology, we propose a leaf volatile profile-based classification model for citrus.

Headspace SPME-GC-MS Analysis and in silico Molecular Docking Studies of Phytochemical Compounds Present in Houttuynia cordata Thunb

“…The initial column temperature was programmed from 40ºC for 1 min to 250ºC at a rate of 5ºC per min, and then to 250ºC for 20 min. 13,14 The relative VOC's constituents were expressed by its peak area percentage. Based on the comparison of mass spectra with those of the 2017 National Institute of Standards and Technology (NIST) GC-MS Libraries the volatile compounds were identified.…”

Origin differentiation based on volatile constituents of genuine medicinal materials Quisqualis indica L. via HS‐GC‐MS, response surface methodology, and chemometrics

“…It has the advantage of rapid and sensitive identification of the volatile organic compounds (VOCs) in plants, which is usually combined with multivariate statistical methods for species identification and geographic traceability. 19,20 In this study, total responsiveness and total peak number were used as evaluation indexes based on one-way test. Incubation temperature, incubation time, and sample amount were examined as factors, and the Box-Behnken RSM was used to optimise the analytical conditions of HS-GC-MS. After identifying the volatile compounds in the database, the similarities and differences of volatile constituents in QIL from different origins were compared in combination with fingerprint and chemometrics, respectively.…”

“…Headspace gas chromatography–mass spectrometry (HS‐GC‐MS) combines the efficiency and convenience of static headspace sampling and the separation and identification capabilities of GC‐MS. It has the advantage of rapid and sensitive identification of the volatile organic compounds (VOCs) in plants, which is usually combined with multivariate statistical methods for species identification and geographic traceability 19,20 …”

Perceptual Effects of Walnut Volatiles on the Codling Moth

“…Plant VOCs are a class of volatile secondary substances emitted from plant organs that promote attraction or avoidance of pests, which provide insights for the development of new ecological pesticides [ 8 , 9 ]. Plant VOCs are related to factors such as variety [ 10 , 11 , 12 ], rootstock [ 13 ], and soil [ 14 ]. They can serve as a medium for information exchange, playing an important role in the olfactory host localization of insects [ 15 , 16 ].…”