Gas chromatography: a mature technique with a bright future in phytochemical analysis

The volatile fraction of a plant is a mixture of compounds that can be recovered because of their ability to vaporise both spontaneously and/or through suitable sampling conditions or techniques. A study of the volatile fraction includes a group of dedicated approaches and/or techniques that produce samples representative of the volatiles characterizing a plant matrix, although with different and mutually non-comparable compositions, e.g. headspace, essential oils and/or extracts obtained by specific techniques. The resulting samples in general imply the adoption of gas chromatography combined with mass spectrometry (GC-MS) as the method of choice for their analysis.

The overwhelming evolution of analysis over the last three decades has dramatically changed not only approaches and strategies in the investigation of the plant volatile fraction, but also induced the advancement of GC and involved techniques. [1]. Over this period, ever-powerful methods/techniques have been introduced, including fast and ultrafast GC, enantioselective GC, GCxGC as such or in combination with tandem and high-resolution mass spectrometry, non-separative methods, as well as dedicated sample preparation techniques on-line coupleable with them (e.g. high concentration capacity techniques), highly effective derivatization techniques or advanced data processing approaches. The evolution of GC and related techniques all together have concurred to extend the range of GC applications to new fields such as one-step methods for effective in-field and/or multitrophic studies or metabolomics applications.

This lecture is an overview of the most recent conventional and non-conventional methods and technologies to be applied to routine analysis of the plant volatile fraction involving GC and related techniques not only in terms of instrumentation but also of operative strategies. These topics will be illustrated with real-world examples taken from the authors' everyday experience.

Keywords: Gas chromatography, Plant volatile fraction, Hyphenated techniques, Dedicated sample preparation techniques.

References:

[1] Cagliero C, Sgorbini B, Cordero C, Liberto E, Bicchi C, Rubiolo P. Analytical strategies for multipurpose studies of a plant volatile fraction. In: Hostettmann K, Stuppner H, Marston A, Chen S, editors. Handbook of Chemical and Biological Plant Analytical Methods, 1st Ed, John Wiley & Sons Ltd.; 2014: 447 – 466