FASTER GAS CHROMATOGRAPHY AND ITS UTILIZATION IN BREWING. PART 1. – THEORETICAL AND PRACTICAL ASPECTS

Importance of the Topic

In modern brewing analytics, laboratories face increasing demands for higher sample throughput, faster turnaround and more efficient use of costly instrumentation. Fast gas chromatography (GC) addresses these requirements by minimizing analysis time without compromising separation quality. This is especially critical in breweries, where rapid control of flavor compounds, fermentation by-products and trace impurities directly impacts product consistency and quality.

Objectives and Overview of the Study

This article reviews the theoretical foundations and practical considerations of speeding up GC analyses for brewing applications. Key goals include evaluating the influence of carrier gas type and control, capillary column dimensions, temperature programming rates and detector design on analysis time and resolution. The work synthesizes historical developments and presents guidelines for selecting optimal conditions to achieve reliable, high-throughput separations.

Used Instrumentation

• Capillary columns with internal diameters from 50 µm up to 530 µm and lengths of 5–50 m
• Electronic pressure control modules for constant flow or constant pressure operation
• Carrier gases: hydrogen, helium, nitrogen
• Oven heating setups: conventional GC oven with insulating inserts; resistively heated metal microtubes enabling 100 °C/s ramps
• Detectors: flame ionization detector (FID) with make-up gas, micro-electron-capture detector (µECD), time-of-flight mass spectrometer (TOF-MS)
• Hydrogen generators to eliminate gas cylinder handling risks

Main Results and Discussion

Studies show that reducing column internal diameter greatly narrows peak widths. For example, columns of 100 µm ID produce peaks roughly nine times narrower than 530 µm ID at equal efficiency, translating into a ninefold speed gain. Hydrogen as a carrier gas offers optimal linear velocities 1.5 times those of helium and 3.3 times those of nitrogen, while maintaining comparable column plate heights. Moreover, hydrogen’s lower gas viscosity and higher optimal flow speeds allow faster separations with minimal efficiency loss. Electronic pressure control maintains constant flow during temperature programming, preventing efficiency losses from viscosity changes at elevated temperatures. Flash heating with microtubes enables oven ramps up to 100 °C/s and rapid cooling (<30 s from 300 °C to 50 °C), further shortening cycle times. Detector dead volumes and data-acquisition rates (≥200 Hz) are critical to preserve peak shape and sensitivity at millisecond peak widths.

Benefits and Practical Applications of the Method

• Drastically reduced GC cycle times increase daily sample throughput in QA/QC and research labs
• Improved utilization of high-cost instruments through faster turnaround
• Enhanced sensitivity and resolution when using hydrogen carrier gas and optimized detectors
• Reliable monitoring of key brewing analytes, including hop volatiles, off-flavor precursors and fermentation metabolites
• Compatibility with mass spectrometric identification enhances confirmation of trace compounds

Future Trends and Potential Applications

Advances in microfabrication may yield even narrower bore columns and micro-GC devices for field or at-line brewery monitoring. Integration of TOF-MS with deconvolution software will facilitate ultra-fast screening of complex flavor profiles. Cryogen-free cooling, automated sampling and machine-learning algorithms for real-time method optimization will further accelerate analyses. Additionally, on-chip heating elements and portable GC-MS platforms promise continuous process control in brewing operations.

Conclusion

Faster gas chromatography, enabled by narrow capillary columns, hydrogen carrier gas, electronic pressure control and high-speed temperature programming, offers significant reductions in analysis time without sacrificing separation performance. Implementing these strategies in brewing laboratories enhances throughput, sensitivity and operational efficiency, supporting tighter process control and product quality assurance.

References

1. Martin A. J. P., Synge R. L. M. A new form of chromatogram employing two liquid phases. Biochem. J. 35, 1941, 1358–1368.
2. James A. T., Martin A. J. P. Gas–liquid partition chromatography: the separation and micro-estimation of volatile fatty acids. Biochem. J. 50, 1952, 679–690.
3. James A. T., Martin A. J. P. Gas–liquid partition chromatography. Analyst 77, 1952, 915–932.
4. Golay M. J. E. Gas Chromatography. Academic Press, New York, 1958.
5. Golay M. J. E. Gas Chromatography. Butterworths, London, 1958.
6. Desty D. H., Goldup A., Swanton W. T. Gas Chromatography. Academic Press, New York, 1962.
7. Sacks R., Smith H., Nowak M. High-speed gas chromatography. Anal. Chem. 70, 1998, 29A–37A.
8. Van Es A., Janssen J., Cramers C. A., Rijks J. Sample enrichment in high-speed narrow-bore capillary gas chromatography. J. High Resol. Chromatogr. 11, 1988, 852–857.
9. Klemp M. A., Akard M. L., Sacks R. D. Cryofocusing inlet with reverse-flow sample collection for GC. Anal. Chem. 65, 1993, 2516–2521.
10. Akard M. L., Sacks R. D. High-speed GC air monitoring using cryointegration. J. Chromatogr. Sci. 32, 1994, 499–505.
11. Dagan S., Amirav A. Fast GC–MS of thermally labile steroids and drugs in supersonic molecular beams. J. Am. Soc. Mass Spectrom. 7, 1996, 737–752.
12. van Deursen M. M., Beens J., Janssen H. G., Leclercq P. A., Cramers C. A. Evaluation of TOF-MS for fast GC. J. Chromatogr. A 878, 2000, 205–213.
13. Korytár P., Matisová E. Fast gas chromatography. Chem. Listy 95, 2001, 470–476.
14. Korytár P., Janssen H. G., Matisová E., Brinkman U. A. Th. Practical fast GC: methods, instrumentation and application. Trends Anal. Chem. 21, 2002, 558–572.
15. Klee M. S., Blumberg L. M. Theoretical and practical aspects of fast GC and method translation. J. Chromatogr. Sci. 40, 2002, 234–247.
16. Blumberg L. M. Theory of fast capillary GC. Part 1: Column efficiency. J. High Resol. Chromatogr. 20, 1997, 597–604.
17. Blumberg L. M. Theory of fast capillary GC. Part 2: Speed of analysis. J. High Resol. Chromatogr. 20, 1997, 679–687.
18. Blumberg L. M., Berger T. A. Molecular basis of peak width in capillary GC under high pressure drop. Anal. Chem. 65, 1993, 2686–2689.
19. Giddings J. C., Seager S. L., Stucki L. R., Stewart G. H. Plate height in gas chromatography. Anal. Chem. 32, 1960, 867–870.
20. David F., Sandra P. Use of hydrogen as carrier gas in capillary GC. Am. Lab. 31, 1999, 18–19.
21. Grand D. W. Capillary Gas Chromatography. Wiley, Chichester, 1996.
22. Korytár P., Matisová E. Instrumentation for fast GC. Chem. Listy 95, 2001, 783–790.
23. Zeeuw de J., Vonk N., Smits R., Gummersbach J. Efficient and fast analysis of a wide range of products using a 0.15 mm ID column. Int. Lab. 29, 1999, 28–30.
24. Leclercq P. A., Cramers C. A. High-speed GC–MS. Mass Spectrom. Rev. 17, 1998, 37–49.
25. Jaulmes A., Ignatiadis I., Cardot P., Vidal-Madjar C. Characterization of peak asymmetry with overloaded capillary columns. J. Chromatogr. 395, 1987, 291–306.
26. Ghijsen R. T., Poppe H., Kraak J. C., Duysters P. P. E. Mass loadability of stationary phases in GC. Chromatographia 27, 1989, 60–66.
27. David F., Gere D. R., Scanlan F., Sandra P. Instrumentation and applications of fast high-resolution GC. J. Chromatogr. 842, 1999, 309–319.
28. van Deursen M. M., Beens J., Cramers C. A., Janssen H. G. Possibilities and limitations of fast temperature programming. J. High Resol. Chromatogr. 22, 1999, 509–513.
29. Dallüge J., Ou-Aissa R., Vreuls J. J., Brinkman U. A. Th., Veraart J. R. Fast temperature programming in GC using resistive heating. J. High Resol. Chromatogr. 22, 1999, 459–464.
30. Annino R. Practical limits of high-speed chromatography: theoretical modeling of commercial GCs. J. High Resol. Chromatogr. 19, 1996, 285–290.
31. Dyson N. Peak distortion, data sampling errors and the integrator in very narrow chromatographic peaks. J. Chromatogr. A 842, 1999, 321–340.