Medical diagnosis using exhaled breath, the search for signs of life in space, and the detection of contaminants in food: separation science is finding applications across an increasingly diverse range of fields. During a session organised by the AFSEP Young Scientists Club at Forum LABO, three early-career researchers presented their work, demonstrating how new analytical approaches can address major challenges in healthcare, space exploration and food safety.

What if a simple breath could one day help diagnose disease or predict whether a patient will respond to treatment?

At the University of Liège, research presented by Thibault Massé focuses on exhaled breath, a particularly promising biological matrix because it can be collected completely non-invasively. More than 1,000 compounds have already been detected and identified in exhaled air. These volatile and semi-volatile molecules can reflect metabolic processes occurring within the body and therefore provide valuable information about a patient’s physiological state.

The objective is to identify biomarkers associated with specific diseases within this metabolic fingerprint. However, analysing exhaled breath remains challenging: sampling must be standardised, environmental contamination controlled and physiological differences between patients taken into account.

To obtain a more detailed characterisation, researchers are using comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS). Adding a second separation dimension makes it possible to distinguish compounds that may overlap in conventional gas chromatography.

This approach has notably been applied to asthma, a chronic inflammatory disease affecting more than 300 million people worldwide.

One of the main challenges is to better characterise different patient profiles in order to provide more appropriate treatments. The research presented during the session showed that a volatile signature in exhaled breath could help distinguish between different asthma phenotypes.

Researchers have also investigated whether these signatures could predict how patients with severe asthma will respond to certain biologic therapies. Volatolomic signatures were able to distinguish responders from non-responders in two independent cohorts studied in Belgium and the United Kingdom.

Among the molecules identified, several aldehydes appear particularly interesting because of their potential relationship with oxidative stress mechanisms. Reducing a complex biological signature to a small number of compounds could eventually pave the way for simpler tools, such as dedicated sensors suitable for clinical use.

The long-term perspective is particularly promising: transforming complex laboratory analysis into a tool that could help clinicians make faster and more personalised treatment decisions.

The second project takes separation science into a completely different environment: space.

Research presented by Gabin Bergerot, a PhD student at the University of Rouen Normandy, focuses on the development of miniaturised gas chromatography systems for space exploration.

Sending an analytical instrument to Mars or another celestial body involves major constraints in terms of mass, volume and energy consumption. Conventional chromatographs therefore need to be radically miniaturised.

One promising solution is based on MEMS technologies, using silicon microfabrication to produce chromatographic microcolumns only a few centimetres in size, with integrated heating systems. The aim is to maintain strong analytical performance while significantly reducing the instrument’s size and energy requirements.

Beyond miniaturisation, this research addresses a fascinating question: how can we search for potential traces of life beyond Earth?

One possible indicator is chirality. Some molecules exist in two mirror-image forms known as enantiomers, much like our left and right hands. Yet life on Earth shows a strong preference for specific forms: most biological amino acids, for example, occur in the L configuration.

Detecting an excess of one enantiomer over another in an extraterrestrial environment could therefore provide an interesting clue, although it would not in itself constitute proof of life.

Researchers are developing chiral microcolumns capable of separating these molecules. Initial results presented during the session showed selectivity across several chemical families as well as for several amino acids.

Ultimately, these technologies could contribute to the development of increasingly compact and efficient chromatographic instruments for future space missions.

Back on Earth, the third application focuses on food safety.

Biocidal products are widely used throughout the food chain to disinfect equipment, protect facilities and control harmful organisms. They play an essential role in managing microbiological risks, but their use can also result in chemical residues in food, particularly when cleaning or rinsing procedures are not properly controlled.

Research presented by Gaëlle Touchet from ANSES therefore aims to identify priority biocidal active substances and assess their presence in food products of animal origin.

A method based on liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) was developed to search for these substances in matrices including cow’s milk and chicken muscle.

One of the strengths of high-resolution mass spectrometry lies in the variety of analytical strategies it enables.

A targeted approach searches for known substances using analytical standards, allowing robust identification and quantification. A semi-targeted approach can then retrospectively analyse the acquired data to search for additional contaminants using databases. Finally, a non-targeted approach compares the chemical fingerprints of samples to identify compounds that were not necessarily being searched for initially.

These strategies are complementary: one confirms what researchers already know to look for, while the others progressively expand the scope of investigation.

Analyses of commercial samples identified several biocide residues in chicken and milk. For substances with established maximum residue limits, the concentrations measured in the samples concerned remained below the regulatory thresholds.

At first glance, these three projects may appear to have very little in common. Yet they share the same underlying ambition: adapting separation technologies to meet new scientific challenges.

In healthcare, the goal is to transform exhaled breath into a source of clinically useful information. In space exploration, laboratory instruments must be miniaturised without losing their separation capabilities. In food safety, analytical methods must expand their scope to detect known, emerging and sometimes unexpected contaminants.

Chromatography and mass spectrometry are therefore no longer simply tools for identifying and quantifying molecules. Their evolution is opening up new ways to diagnose disease, explore new worlds and monitor our environment.

Behind these innovations lies another important objective of the session: highlighting a new generation of scientists who are helping shape the future of separation science.

Article based on the session dedicated to “Separation Science for Tomorrow’s Research”, organised by the AFSEP Young Scientists Club at Forum LABO.