Flavor and Fragrance GC/MS Analysis with Hydrogen Carrier Gas and the Agilent HydroInert Source

Significance of the Topic

Flavor and fragrance (F&F) compounds are complex mixtures of natural and synthetic volatile components widely used in food, beverage, cosmetic and industrial products. Accurate characterization of these mixtures is essential for quality control, product consistency and consumer safety. Gas chromatography coupled to mass spectrometry (GC/MS) is the gold standard for F&F analysis, offering high chromatographic resolution and reliable mass spectral identification. However, traditional GC/MS methods rely on helium as the carrier gas, which faces supply constraints and rising costs. Transitioning to hydrogen carrier gas offers a sustainable and cost-effective alternative but poses challenges due to hydrogen’s reactivity in the electron ionization source.

Objectives and Study Overview

This application note evaluates the use of the Agilent HydroInert electron ionization source for GC/MS and GC/MS/MS analysis of flavor and fragrance mixtures with hydrogen carrier gas. The study aims to compare spectral fidelity, library matching, peak shape and analysis speed against conventional helium methods and standard extractor sources. It also demonstrates the method’s applicability to real-world essential oil samples.

Methodology and Instrumentation

Analytical configuration:

• Agilent 8890 GC system with split/splitless inlet, Ultra Inert low pressure drop liner and J&W DB-WAXetr column (30 m × 250 µm × 0.25 µm).
• Agilent 5977B GC/MSD fitted with the HydroInert electron ionization source and a 9 mm extractor lens.
• Hydrogen carrier gas generated on-site at a constant flow of 1.4 mL/min.
• Oven temperature program: 45 °C (4 min) to 220 °C at 8 °C/min, then to 230 °C at 8 °C/min with appropriate holds.
• Electron ionization at 70 eV, source temperature 280 °C, quadrupole temperature 150 °C, mass range 40–250 m/z in full scan mode.

Samples included a standard mixture of 13 F&F compounds and orange and lemon essential oils. Agilent MassHunter Unknowns Analysis software performed spectral deconvolution and matched spectra against the Wiley Flavors and Fragrances library with a minimum match score threshold of 75.

Main Findings and Discussion

Implementing the HydroInert source with hydrogen carrier gas significantly improved chromatographic peak shapes, notably reducing tailing of late-eluting high-boiler analytes such as maltol. Spectral fidelity increased, with library match scores rising by over 10% for several target compounds compared to a standard extractor source. The optimized hydrogen method halved total run time from 82 min (helium) to 41 min without compromising resolution. Analysis of orange and lemon essential oils yielded 42 and 54 compound identifications, respectively, most achieving match scores above 80.

Benefits and Practical Applications of the Method

• Reduced dependence on helium by using on-site hydrogen generation.
• Enhanced spectral integrity and higher confidence in library matching.
• Improved peak symmetry and reduced tailing for better quantitation.
• Significant run-time reduction, increasing laboratory throughput.
• Applicable to food, beverage, fragrance development and QA/QC laboratories.

Future Trends and Opportunities

As helium availability remains limited, hydrogen-compatible ion sources like the HydroInert are poised to become industry standard. Future developments may include further source optimization, integration with automated hydrogen supply systems, expanded deconvolution software and customized spectral libraries for hydrogen-driven spectra, as well as adoption of tandem MS and machine learning approaches for advanced compound profiling. These innovations will support sustainable, high-throughput F&F analysis and regulatory compliance.

Conclusion

The Agilent HydroInert electron ionization source effectively addresses the challenges of using hydrogen as a GC carrier gas, delivering sharper peaks, improved spectral fidelity and faster analysis for flavor and fragrance profiling. This approach offers laboratories a sustainable, high-performance alternative to helium-based methods.

Reference

1. Rubiolo P et al. Gas Chromatography in the Analysis of Flavors and Fragrances. Practical Gas Chromatography. Springer Berlin Heidelberg; 2014. pp 717–743.
2. Petruzzi D. Flavor and fragrances market worldwide: Statistics & Facts. May 19, 2022.
3. Quimby BD, Andrianova AA. Volatile Organic Compounds Analysis in Drinking Water with Headspace GC/MSD Using Hydrogen Carrier Gas and HydroInert Source. Agilent Technologies Application Note 5994-4963EN; 2022.
4. Agilent Technologies. Inert Plus GC/MS System with HydroInert Source. Technical Overview 5994-4889EN; 2022.
5. Agilent Technologies. EI GC/MS Instrument Helium to Hydrogen Carrier Gas Conversion. User Guide 5994-2312EN; 2022.