Continued helium use in gas chromatography–mass spectrometry/flame ionization detection has proven problematic. To combat this, alternative efforts are being tested.
University of Turin and University of Messina (Italy) researchers investigated alternatives carrier gases to helium for gas chromatography–mass spectrometry/flame ionization detection (GC–MS/FID). Their procedures were published in the Journal of Chromatography A (1).
Fragrances and corresponding raw materials are complex mixtures, typically containing between 20 and 200 various synthetic or natural organic substances; proper identification and quantification of these components can be challenging. Variations in the amounts of these ingredients contribute to differences in odor perception and olfactory response. The fragrance industry conducts quality control (QC) analyses for qualitative and quantitative purposes. Qualitatively, the goal is to analyze the chemical profile of the fragrance and correlate it with its organoleptic characteristics. Quantitatively, the focus is on measuring the concentration of specific substances to ensure compliance with international regulatory standards.
One type of substance that has proven notable are the potential allergens found in Annex III of Regulation (EC) No 1223/2009, as amended by Commission Regulation (EU) 2023/1545, based on the opinion of the Scientific Committee on Consumer Safety. These substances can be problematic if their concentration exceeds 0.01% in rinse-off products and 0.001% in leave-on cosmetic products. This has made it vital for fragrance ingredients to be vigorously tested to verify their compliance with QC specifications. Volatile compound QC is typically performed with gas chromatography (GC) with a flame ionization detector (FID) or coupled with mass spectrometry (MS) for identification and quantification, or to define fragrance profiles based on compounds’ relative percentage abundance.
Helium has been the preferred carrier gas choice for GC–MS analysis, due to its inertness, wide optimum linear velocity range, safety, and purity. However, its status as a non-renewable resource, alongside periodic supply shortages and rising costs, has proved to be a challenge for laboratories and industries that rely on it. Among potential alternatives, hydrogen and nitrogen are believed to be the most suitable, though each come with notable advantages and limitations.
Hydrogen has a high diffusion coefficient and low viscosity, allowing for faster analyses and improved performances; however, its flammability and potential reactivity act as barriers to widespread adoption. Nitrogen has been proven to be safe, inert, and abundantly available; however, its lower optimum linear velocity increases analysis time, while its higher ionization capacity significantly reduces the sensitivity of GC–MS analyses.
In this study, the scientists aimed to develop and evaluate alternative analytical methods for fragrance analysis by replacing helium with the alternative gases in GC–MS/FID. With conventional (0.25 mm dc) and reduced internal diameter (0.18 mm dc) columns, hydrogen and nitrogen were evaluated against the reference helium method for the analysis of complex fragrances. Method translation involved flow rate optimization and temperature programs to achieve faster analysis times. Quantitative and qualitative performances were compared by assessing resolution, limits of detection and quantification, spectral similarity, absolute and relative quantification.
The results showed that hydrogen-based methods, especially when gas generators were used, achieved more balanced performances with reduced energy consumption and lower environmental footprints, maintaining robust analytical capabilities. The reduced internal diameter column configuration further enhanced method efficiency by decreasing analysis time and reagent usage, increasing its suitability for green analytical chemistry (GAC) applications.
Overall, the findings support hydrogen’s implantation as an alternative to helium in fragrance quality control. Future research will focus on optimizing nitrogen-based methods to enhance sensitivity and exploring strategies to improve the environmental footprint of fragrance analysis, all while maintaining regulatory compliance and analytical reliability
(1) Bechis, G.; Arena, A.; Bicchi, C.; Rubiolo, P.; et al. Greener Analytical Methods for Fragrance Quality Control: Replacing Helium with Hydrogen and Nitrogen in Gas Chromatography–Mass Spectrometry/Flame Ionization Detection. J. Chromatogr. A 2025, 1758, 466179. DOI:
