Comprehensive Two-Dimensional Gas Chromatography-Mass Spectrometry as a Tool for the Untargeted Study of Hop and Their Metabolites.

Since hop secondary metabolites have a direct correlation with the quality of beer and other hop-based beverages, and the volatile fraction of hop has a complex composition, requiring effective separation, here we explore the application of headspace solid-phase microextraction as a sample preparation method, coupled with comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) analysis. The methodology involved the use of a DVB/PDMS fibre with 500 mg of hop cone powder, extracted for 40 min at 50 °C, for both GC-MS and GC×GC-MS. The varieties Azacca, Cascade, Enigma, Loral, and Zappa were studied comprehensively.

Lipase-catalysed changes in essential oils revealed by comprehensive two-dimensional gas chromatography.

Candida antarctica lipase A (CALA) was applied for the chemo-selective enzymatic transesterification of terpene and phenyl alcohols in 35 different essential oil samples. Comprehensive two-dimensional gas chromatography with mass spectrometry (GC×GC‒MS) analysis enabled the separation and tentative identification of a cohort of 125 compounds, allowing the instant visualisation of the reaction process changes, amid the complex chemical background of the samples. The results indicate that 42 out of 79 alcohols so-identified were fully or partially esterified within 48 h of reaction, with primary alcohols being the substrates of preference of the enzyme (90-100% conversion), followed by secondary alcohols (mostly ~ 80-100% conversion).

Quantitative assessment of enzymatic processes applied to flavour and fragrance standard compounds using gas chromatography with flame ionisation detection.

The performance of different enzymes towards the bioprocessing of aroma-related compounds was investigated and a strategy based on GC-FID analysis was developed to facilitate assessment of the stages of characterisation, screening and optimisation, including chiral ratio determination. Characterisation included activity assays (UV-Vis and GC-FID), protein quantification (NanoDrop spectrophotometry) and molar mass estimation (SDS-PAGE electrophoresis). Screening experiments assessed different enzymes, substrates, solvents, acyl donors or mediators.

The Blossoming of Technology for the Analysis of Complex Aroma Bouquets-A Review on Flavour and Odorant Multidimensional and Comprehensive Gas Chromatography Applications.

Multidimensional approaches in gas chromatography have been established as potent tools to (almost) attain fully resolved analyses. Flavours and odours are important application fields for these techniques since they include complex matrices, and are of interest for both scientific study and to consumers. This article is a review of the main research studies in the above theme, discussing the achievements and challenges that demonstrate a maturing of analytical separation technology.

Ionic liquid capillary columns for analysis of multi-component volatiles by gas chromatography-mass spectrometry: performance, selectivity, activity and retention indices.

This study investigates applications and performance evaluation of SLB-IL60, SLB-IL76 and SLB-IL111 columns, in relation to a DB-Wax column, for the analysis of coffee volatile compounds. Both standards and an authentic coffee sample were analysed, with solid-phase microextraction (SPME) sampling of the latter. A cryofocusing method was applied to improve resolution of the earliest eluting peaks using splitless injection SPME sample analysis.