Industry Roundup: Vacuum Gives Markes International’s HiSorb Extraction a New Dimension

In headspace sorptive extraction, the sorbent is rarely the limiting factor. The bottleneck is the transfer of analytes from the sample matrix into the vapor phase. Semi-volatiles and compounds with low affinity for the headspace partition slowly, so they are under-represented in the resulting chromatogram. The usual remedies, higher extraction temperatures and longer equilibration times, improve recovery but risk thermal degradation, artefact formation and profiles that no longer reflect the original sample.

Markes’ Vac-HiSorb takes a different route. Per the company’s website,¹ Vac-HiSorb combines the high sorptive capacity of HiSorb with vacuum-assisted extraction (VAE), making pressure a method parameter alongside temperature, time and agitation.

Why Reduced Pressure Helps

Evacuating air from the sealed vial before extraction promotes the transfer of analytes from the sample into the headspace. At reduced pressure, gas-phase diffusion is faster, lowering resistance to mass transfer on the headspace side of the interface. The gain is largest for analytes whose volatilization is otherwise rate limiting: semi-volatile compounds and those with low affinity for the headspace.

Professor Elia Psillakis of the Technical University of Crete, whose research pioneered vacuum-assisted headspace extraction, sees clear value in applying the principle to high-capacity sorbents.

“Vacuum introduces another dimension to headspace extraction by helping compounds move from the sample into the headspace faster and more efficiently,” she reported. “Extending this principle to high-capacity sorptive extraction is particularly interesting because it gives us the opportunity to recover compounds that can be difficult to access under conventional conditions, while using milder extraction conditions.”

Workflow and Instrumentation

Vac-HiSorb retains HiSorb’s solvent-free extraction. Air evacuation and extraction are performed manually, after which the HiSorb probe is transferred into an empty thermal desorption tube. Subsequent thermal desorption–gas chromatography (TD–GC) analysis can then be fully automated on a compatible thermal desorber.

The approach runs on existing Markes systems, including UNITY–xr, UNITY–ULTRA-xr, TD100–xr and Centri 180. Laboratories already using HiSorb can therefore evaluate VAE without investing in new analytical hardware.

Chili Flakes: Wider Coverage, Stronger Late Elution

In a comparison with conventional HiSorb sampling of chili flakes, VAE increased both the number of compounds detected and their abundance. The largest enhancement was among later-eluted compounds, consistent with improved recovery of less volatile species.

Gains spanned oxygenated compounds, nitrogen-containing compounds, terpenes and terpenoids:

A range of terpenes and terpenoids were detected almost exclusively in the Vac-HiSorb sample, pointing to analytes that conventional conditions largely miss.

Milder Conditions, More Representative Data

Because vacuum accelerates release into the headspace, extraction can be faster and run under milder conditions. Less reliance on elevated temperatures or long extraction times helps preserve temperature-sensitive samples and minimizes artefacts, supporting more representative characterization.

Reusable vacuum closures, along with the potential for lower temperatures, reduced agitation and shorter extraction times, can also help laboratories cut waste and energy consumption.

Where It Fits

Markes positions Vac-HiSorb for exploratory research, method optimization and comprehensive characterization of complex samples, from food and beverage and aroma and flavor work to environmental analysis. With evacuation handled manually and desorption and GC analysis automated, it lends itself to comparative studies that test the effect of pressure on a given matrix before a routine protocol is fixed. In addition, for analysts whose methods have long been tuned by temperature and time alone, it offers a third lever: pressure.

In short, Vac-HiSorb tackles the rate-limiting step of headspace sorptive extraction by lowering the pressure in the sample vial. The chili flake data show broader compound coverage and markedly higher abundances, especially for later-eluting analytes, while milder conditions help protect sample integrity. Because it runs on existing Markes thermal desorbers, HiSorb users can explore vacuum-assisted extraction with minimal disruption to their TD–GC workflows.

References

1. Markes Introduces Vac-HiSorb for More Comprehensive Headspace Analysis. Markes website.https://markes.com/news/2026/markes-introduces-vac-hisorb-for-more-comprehensive-headspace-analysis (accessed 2026-10-26)