Simple Aroma Component Analysis Using Nexis GC-2060 with a Multi-Mode Inlet (MMI)

Significance of the topic

Aroma profiling is central to quality control, product development and sensory evaluation in food and beverage industries. Rapid, sensitive and cost-effective analytical workflows that minimize laborious sample preparation enable routine screening of volatile and semi-volatile aroma compounds and help producers link process variables to sensory outcomes.

Objectives and study overview

This application note demonstrates a simplified workflow for aroma analysis of alcoholic beverages by combining a MonoTrap silica monolith sorbent for headspace collection with thermal desorption in a Multi-Mode Inlet (MMI) installed on a Nexis GC-2060 gas chromatograph. The goals were to (1) show that MonoTrap collection plus MMI thermal desorption can deliver high sensitivity without complex extraction equipment, (2) compare aroma profiles across beverage types (sake and diverse beers), and (3) evaluate process effects (hop contact time) on hop-derived volatiles.

Methodology

Sample collection and preparation:

• Samples: two sake types (regular and daiginjo) and several beers (pilsner, saison, IPA). For hop-contact study, two saison variants differing only in hop contact time (24 h vs 48 h) were compared.
• Preparation: 5 g sample + 3 g NaCl in 20 mL vial; 50 µL of 1% 1-pentanol as internal standard; MonoTrap RGPS TD sorbent suspended in vial headspace; incubation at 40 °C for 30 min.

Thermal desorption and GC conditions (summary):

• Nexis GC-2060 with Multi-Mode Inlet (MMI) in thermal desorption/extraction mode; insert loaded with MonoTrap following Easy sTop procedure (tool-free insert access).
• Carrier gas: hydrogen (cost-saving); column: SH-PolarWax (30 m × 0.25 mm, 0.50 µm); detector: FID with N2 make-up and H2/air combustion gases.
• MMI heating: rapid ramping (up to 1000–1200 °C/min reported) for sharp peak shapes; purge/split programs and desorption parameters set to transfer analytes to column; compressed-air cooling used to accelerate cycle time (~10 min cooling observed under these conditions).

Applied instrumentation

Key instruments and consumables used in the study:

• Shimadzu Nexis GC-2060 gas chromatograph.
• Multi-Mode Inlet (MMI) for the Nexis GC-2060 supporting thermal desorption/extraction.
• MonoTrap RGPS TD silica monolith sorbent (GL Sciences) and MT holder for headspace sampling.
• Column: SH-PolarWax (30 m, 0.25 mm I.D., 0.50 µm).
• Detector: Flame Ionization Detector (FID).

Main results and discussion

General findings:

• The combination of MonoTrap headspace trapping and MMI thermal desorption provided sensitive detection of characteristic aroma compounds with minimal sample-preparation equipment.
• Rapid MMI temperature ramping and option for compressed-air cooling enabled relatively short analysis cycles.

Sake comparison (regular vs daiginjo):

• Daiginjo sake showed substantially higher area ratios for esters associated with “ginjo-ka” (fruity aromas), notably ethyl caproate (apple-like) and isoamyl acetate (banana-like), consistent with higher rice polishing ratios producing stronger fruity aromas.
• Overlay chromatograms highlighted pronounced ethyl caproate differences between the two sake types.

Beer style comparison (pilsner, saison, IPA):

• Ales (saison and IPA) exhibited larger area ratios for certain esters (e.g., ethyl caproate) and hop-derived terpenes (myrcene, linalool, geraniol) compared with the pilsner (lager), which tended to show higher acetate-ester signals such as isoamyl acetate and β-phenethyl acetate in some cases.
• Terpene peaks were minor or absent in the pilsner chromatogram but prominent in saison and IPA, matching sensory descriptors of fruity/citrus and floral notes in those beers.
• Within ales, IPA had higher 2-phenylethyl alcohol (rose-like) than the saison studied, showing that style-specific aroma signatures are resolvable.

Effect of hop contact time (saison 24 h vs 48 h):

• Increasing hop contact time from 24 to 48 h increased ester and terpene signals, with terpenes increasing by ~30% in this experiment, demonstrating the method’s utility to monitor process variables that influence hop-derived aroma.
• Higher alcohols were largely unaffected by hop contact time in this dataset.

Practical benefits and applications

Advantages demonstrated by the approach:

• Minimal sample-preparation overhead: direct headspace trapping on MonoTrap avoids solvent extraction or SPME fiber handling.
• High sensitivity and ability to detect low-abundance terpenes and esters relevant to flavor profiling.
• Operational flexibility: MMI supports multiple injection modes (split/splitless, PTV, large-volume, thermal desorption) enabling the same inlet to serve diverse laboratory workflows.
• Cost-efficiency: use of hydrogen carrier gas and elimination of dedicated thermal desorption hardware reduce per-sample cost and equipment needs.
• Maintenance convenience: Easy sTop function and tool-free insert access simplify insert exchange and reduce downtime.

Use cases:

• Quality control and batch comparison in breweries and sake production.
• R&D for formulation, process optimization, and sensory-directed product development.
• Screening studies linking production parameters (e.g., rice polishing, hop contact time) to volatile profiles.

Limitations and practical considerations

• Cooling times depend on instrument settings and cooling method; compressed-air cooling required about 10 minutes between analyses in this study, but results may vary.
• Quantitation in the study relied on peak area ratios to an internal standard; full validation (linearity, LOD/LOQ, matrix effects) would be required for regulatory or absolute quantitation.
• FID detection provides good sensitivity for hydrocarbons and many volatiles but lacks structural confirmation capability—GC-MS coupling would improve compound identification confidence.

Future trends and potential applications

Opportunities to expand and enhance the workflow include:

• Integration with mass spectrometry (MMI-TD–GC–MS) for definitive identification and trace-level speciation of isomers and unknowns.
• Automation of headspace trapping and MMI insert handling to increase throughput and reproducibility.
• Use of cryogenic cooling (liquid nitrogen) or enhanced forced-air cooling to shorten cycle times further.
• Broader adoption of optimized sorbent chemistries and selective coatings to target specific compound classes (terpenes, sulfur compounds, etc.).
• Method validation and development of standardized protocols for industrial QC labs and inter-lab comparisons.
• Combining volatile profiling with sensory and chemometric analysis for rapid prediction of sensory attributes and shelf-life changes.

Conclusion

The study demonstrates a practical, sensitive workflow for aroma analysis using MonoTrap headspace collection and thermal desorption in an MMI-equipped Nexis GC-2060. The approach allows discrimination of aroma signatures between beverage types (sake and beer styles) and detection of process-dependent changes (hop contact time) without dedicated thermal-desorption hardware or extensive sample preparation. The MMI’s versatility and rapid heating/cooling options make it a useful platform for routine flavor profiling, R&D and production monitoring in the food and beverage sector.

References

Shimadzu Corporation. Simple Aroma Component Analysis Using Nexis GC-2060 with a Multi-Mode Inlet (MMI). First Edition, March 2026. Acknowledgements: Far Yeast Brewing Co., Ltd. and ISEKADO (Isekadoya Brewery) for sample cooperation.