Hexane is one of the most widely used extraction solvents in the global food system. Derived from petroleum, it plays a central role in efficiently extracting vegetable oils from crops such as soy, sunflower, rapeseed, and corn. The same process produces protein-rich oilseed meals that are widely used in animal feed. From a technological perspective, hexane is effective, inexpensive, and well understood. From a toxicological and regulatory perspective, however, it is increasingly under scrutiny.In the European Union, “technical hexane” is authorized as a food extraction solvent under Directive 2009/32/EC. Its last full safety assessment by the EU’s Scientific Committee on Food dates back to 1996. In 2024, the <a target="_blank" rel="noopener noreferrer" href="https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/sp.efsa.2024.EN-9001">European Food Safety Authority</a> (EFSA) concluded that this assessment is no longer sufficient and formally called for a re-evaluation. The reasons are scientific rather than sensational: technical hexane is not a single pure compound, its impurities are poorly specified, human absorption of n-hexane is well documented, and exposure—particularly for infants and young children—may have been underestimated under current regulatory assumptions.At the same time, public attention has intensified. Investigations commissioned by <a target="_blank" rel="noopener noreferrer" href="https://www.greenpeace.fr/scandale-sanitaire-lhexane-un-solvant-toxique-dans-vos-assiettes/">Greenpeace</a> reported detectable hexane residues in a wide range of everyday foods, including vegetable oils, butter, milk, infant formula, and poultry. While the measured levels generally fall within current legal limits, these <a target="_blank" rel="noopener noreferrer" href="https://www.theexamination.org/articles/processing-agent-hexane-found-in-everyday-foods-renewing-concerns-about-toxic-chemical">findings</a> highlight a critical gap between regulatory compliance and public expectations of food safety and transparency. Processing aids like hexane are not listed on labels, even though trace residues may remain in final products.From a scientific standpoint, the debate raises several important questions. How robust are existing toxicological datasets for chronic, low-level exposure? Do current analytical methods sufficiently characterize impurities and residues across complex food matrices? And should efficiency-driven processing choices be reconsidered when safer—though potentially less economical—alternatives exist?EFSA’s conclusion is cautious but clear: there is no immediate acute health concern, but the available evidence is insufficient to confidently assess long-term risks. As new toxicological data emerge and analytical capabilities improve, hexane has become a case study in how legacy food technologies can outpace the science and regulation designed to govern them. The outcome of the ongoing re-evaluation may shape not only future solvent use, but also broader expectations around transparency, precaution, and trust in the food system.<h3>Global inconsistencies in safety standards</h3>Hexane regulation varies widely across jurisdictions. European limits are among the most conservative, yet they rely heavily on industry-generated data. In other regions, allowable residue levels are significantly higher, and in some cases, hexane use in food and feed is largely unrestricted. This variability complicates global risk assessment and raises questions about harmonization and scientific consistency in food safety governance.<h3>Beyond compliance: Rethinking food processing choices</h3>The ongoing re-evaluation of hexane illustrates a broader challenge in food science: technologies adopted for efficiency and cost-effectiveness may persist long after their safety assumptions become outdated. The issue is not whether hexane poses an immediate public health crisis—EFSA has explicitly stated that it does not—but whether current scientific evidence is sufficient to justify its continued widespread use without further scrutiny.Advances in analytical chemistry now allow more sensitive detection of residues and impurities, while modern toxicology places greater emphasis on long-term, low-dose effects. At the same time, alternative extraction technologies, though less efficient, are becoming more viable as sustainability and safety considerations gain weight.<h3>What are the best methods for detection?</h3>Detection options<ul><li>HS-GC-FID: robust, sensitive for hydrocarbons, widely used for routine control (often aligned with “official” oil methods such as AOCS workflows referenced in the literature).</li><li>HS-GC-MS: adds spectral ID confirmation (useful when there are interferences or you want stronger identity evidence).</li></ul>Quantification<ul><li>Prefer internal standard calibration (often a similar volatile hydrocarbon not expected in the sample) and matrix-matched calibration where feasible.</li></ul><h3>Conclusions</h3>EFSA concluded that there is a need to re-evaluate the safety of technical hexane used as an extraction solvent in the production of foodstuffs and food ingredients. A key aspect of this re-evaluation concerns the accurate characterization and quantification of hexane residues and related hydrocarbons, where <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products?category=1&amp;manufacturerItems=3">gas chromatography (GC)</a> plays a central role. Robust GC-based analytical methods are essential to reliably determine residual solvent levels, distinguish between different hexane isomers and impurities, and ensure compliance with regulatory limits.Advances in GC methodology, including improved separation, sensitivity, and detection capabilities, can significantly reduce analytical uncertainty and support more precise exposure assessments. High-quality GC data are therefore critical for refining dietary exposure estimates, identifying potential sources of variability, and supporting a science-based risk assessment. Strengthening analytical controls through validated GC methods will be an important component of addressing EFSA’s safety concerns and ensuring continued consumer protection.Visit us on&nbsp;<a target="_blank" rel="noopener noreferrer" href="https://www.linkedin.com/showcase/72003132/admin/dashboard/">LinkedIn:</a>&nbsp;#hexaneSafety, #GC-FID #GC-MS<section><blockquote><h5>Petra Gerhards</h5>Petra Gerhards, Dipl-Ing, is Regional Marketing Manager of GC and GC-MS for EMEA at Thermo Fisher Scientific. She has more than 29 years of experience in the fields of GC-MS, SPE and LC-MS. Since joining the regional team she has contributed to workflow solutions combining vials and closures with SPE solutions, GC-MS and LC-MS. She works with KOL's on data for regional specific marketing campaigns, organizes in-house seminars and works on customer specific solutions. Her main expertise is in the field of doping and drugs-of-abuse analysis.</blockquote></section>

Hexane in Food: When Processing Chemistry Meets Public Health

The quality of drinking water is under closer scrutiny than ever before. Beyond microbiological safety and major chemical contaminants, trace-level organic compounds increasingly determine whether water is perceived as clean, safe, and acceptable by consumers. Among these substances, volatile organic compounds (VOCs) play a central role — both from a regulatory and a sensory perspective.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Fisher_Scientific_VOC_Analysis_in_Drinking_Water_Achieving_ppt_Level_Sensitivity_with_ITEX_Dynamic_Headspace_GC_MS_b4de2f994a.jpg" alt="Thermo Fisher Scientific: VOC Analysis in Drinking Water: Achieving ppt-Level Sensitivity with ITEX Dynamic Headspace GC-MS" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Fisher_Scientific_VOC_Analysis_in_Drinking_Water_Achieving_ppt_Level_Sensitivity_with_ITEX_Dynamic_Headspace_GC_MS_b4de2f994a.jpg 245w," sizes="100vw" width="1024" height="512">Modern analytical laboratories face a dual challenge: complying with stringent legal requirements while simultaneously detecting compounds that are noticeable by humans at concentrations far below established health-based limits. This is particularly true for odor-active VOCs, where customer complaints may arise even when water is fully compliant.<h3>What are VOCs — and why are they so challenging?</h3>VOCs are a heterogeneous group of compounds defined primarily by their physical properties rather than their chemical structure. They typically exhibit:<ul><li>Low molecular weight</li><li>Relatively low boiling points (approximately 50–260 °C)</li><li>High vapor pressure</li><li>Low to moderate solubility in water</li></ul>This group includes substances such as light halogenated hydrocarbons (LHKW), aromatic hydrocarbons (BTEX), and trihalomethanes (THMs), many of which are regulated in drinking water due to toxicological concerns or their role as disinfection by-products from an analytical standpoint, these same properties make VOCs difficult to quantify at ultra-trace levels. Losses during sample handling, insufficient enrichment, and water interference can all limit sensitivity — especially when target concentrations are in the low µg/L or ng/L range.<h3>Regulatory pressure drives method sensitivity</h3>European drinking water legislation defines not only maximum allowable concentrations but also strict performance criteria for analytical methods. <a target="_blank" rel="noopener noreferrer" href="https://eur-lex.europa.eu/eli/dir/2009/90/oj/eng?utm_source=chatgpt.com">Directive 2009/90/EC</a> requires limits of quantification to be no higher than 30% of the applicable environmental quality standard. For many VOCs, this translates directly into ppt-level analytical requirements.As a result, laboratories must rely on techniques that go beyond conventional workflows while still maintaining robustness, reproducibility, and ease of use.<h3>Headspace GC-MS: established — but not always sufficient</h3>Headspace GC-MS remains a cornerstone of VOC analysis in water. <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/64">Static headspace</a> (SHS) methods are widely used due to their simplicity, cleanliness, and compatibility with routine laboratories. However, SHS relies on a single equilibrium extraction of the gas phase, which can limit sensitivity — particularly for very volatile compounds or analytes present at trace concentrations.For these applications, additional enrichment steps are often required.<h3>ITEX dynamic headspace: turning sampling into enrichment</h3><a target="_blank" rel="noopener noreferrer" href="https://www.thermofisher.com/order/catalog/product/1R77010-1125">ITEX (In-Tube Extraction) Dynamic Headspace</a> bridges the gap between simplicity and sensitivity. Unlike static headspace, ITEX repeatedly draws defined volumes of headspace gas through an adsorbent trap, actively enriching analytes before injection into the GC system.This dynamic approach offers several decisive advantages:<ul><li>True analyte enrichment directly from the headspace</li><li>Solvent-free sample preparation</li><li>Reduced risk of contamination and carryover due to a closed, syringe-based design</li><li>Straightforward maintenance with easy access to trap and syringe components</li></ul>By passing the headspace through the trap multiple times, ITEX effectively increases the sampled analyte mass without increasing sample volume — a key advantage for ppt-level analysis.<h3>Tailored adsorbents for targeted performance</h3>ITEX performance can be optimized through the selection of appropriate adsorbent materials:<ul><li>Tenax TA for volatile and semi-volatile compounds</li><li>Carbopack for hydrophobic analytes with minimized water displacement</li><li>Carboxen and Carbosieve materials for very volatile compounds such as vinyl chloride</li></ul>This flexibility allows laboratories to adapt ITEX methods to a wide range of drinking water applications, from regulatory VOC panels to specialized odor investigations.<h3>Managing water — without compromising sensitivity</h3>Water is often the hidden enemy of trace VOC analysis. In ITEX, excess water can be efficiently removed by purging the trap with inert gas at low temperature before thermal desorption. The trap itself can then be heated to temperatures of up to 350 °C, ensuring complete desorption of analytes while maintaining excellent repeatability.Carryover testing demonstrated values of ≤0.027% for all analytes, even without blank subtraction — a critical requirement for trace analysis in regulated environments.<h3>Chromatographic focusing for very volatile compounds</h3>Highly volatile VOCs remain chromatographically challenging, even after enrichment. Combining ITEX with <a target="_blank" rel="noopener noreferrer" href="https://www.thermofisher.com/content/lifetech/global/en/home/industrial/chromatography/gas-chromatography-gc/gc-systems/modules.html">PTV injection</a> and dedicated focusing liners significantly improves peak shape and signal-to-noise ratio. This double-focusing approach is especially effective for compounds such as vinyl chloride and other light halogenated hydrocarbons. When paired with SIM acquisition in <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/484">GC-MS</a>, the result is robust, sensitive, and selective detection across a broad VOC range.<h3>Taste and odor: why ppt really matters</h3>One of the most demanding applications in drinking water analysis is the detection of odor-active compounds such as geosmin. Produced naturally by cyanobacteria and actinomycetes, geosmin causes an earthy, musty taste and odor that consumers can detect at concentrations as low as 5–10 ng/L.Although geosmin poses no health risk, even trace levels can trigger complaints and damage public trust. ITEX Dynamic Headspace GC-MS enables reliable detection well below the sensory threshold, supporting proactive water quality management rather than reactive troubleshooting.<h3>Automation and flexibility for the modern laboratory</h3>Drinking water laboratories often analyze a wide range of sample types and concentration levels. Automated platforms such as the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/422">TriPlus RSH SMART</a> autosampler support multiple injection and sampling techniques — including liquid injection, static headspace, SPME, and ITEX — with automatic tool change functionality.Intelligent sequence control and consumable monitoring help laboratories maximize productivity while maintaining consistent analytical performance.<h3>Conclusion: a future-proof approach to VOC analysis</h3>ITEX Dynamic Headspace has proven to be a powerful and versatile alternative to purge-and-trap for the analysis of VOCs in drinking water. Its ability to deliver ppt-level sensitivity, combined with operational simplicity and excellent robustness, makes it ideally suited for both regulatory compliance and advanced odor analysis.When integrated with PTV injection and SIM-based GC-MS detection, ITEX-DHS supports reliable quantification of even the most challenging VOCs — helping laboratories meet today’s requirements while preparing for tomorrow’s expectationsCall to action:To learn more about this interesting technology in a FREE webinar, register here:<ul><li><a target="_blank" rel="noopener noreferrer" href="https://event.on24.com/wcc/r/5250532/C85F8F6AC85928EE5DB65E38D3C9B23F">April 23-Trinkwasserübewachung mit der ITEX</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://event.on24.com/wcc/r/5250534/258DDD452DE6AAA5FDEB0E72CBF70889">June 11th VOC Analytik in Trinkwasser mittels Headspace GC-MS und ITEX</a></li></ul><h3>Acknowledgement</h3>I would like to thank Dr. Klaus Schrickel, Thermo Fisher Scientific Dreieich, Germany, for the contribution to this blog.<ul><li>Visit us on&nbsp;<a target="_blank" rel="noopener noreferrer" href="https://www.linkedin.com/showcase/72003132/admin/dashboard/">LinkedIn:</a>&nbsp;#GC #GC/MS # ITEX #Headspace</li></ul><blockquote><h5>Petra Gerhards</h5>Petra Gerhards, Dipl-Ing, is Regional Marketing Manager of GC and GC-MS for EMEA at Thermo Fisher Scientific. She has more than 29 years of experience in the fields of GC-MS, SPE and LC-MS. Since joining the regional team she has contributed to workflow solutions combining vials and closures with SPE solutions, GC-MS and LC-MS. She works with KOL's on data for regional specific marketing campaigns, organizes in-house seminars and works on customer specific solutions. Her main expertise is in the field of doping and drugs-of-abuse analysis.</blockquote>

VOC Analysis in Drinking Water: Achieving ppt-Level Sensitivity with ITEX Dynamic Headspace GC-MS

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