The Riva Renaissance: Advancing Cryomodulated Comprehensive GC×GC

Why is the Riva Conference important to you and why should people attend?

One of the main advantages of conferences is the opportunity to engage directly with those presenting lectures and posters. These interactions offer insights into the finer points that can determine the success or failure of adopting new methods in your laboratory. The Riva Conference stands out because its organizers have gone above and beyond to encourage active exchange between presenters and attendees. By taking part in the Riva Conference, you not only stay up to date with the latest advances but you also gather essential details to effectively apply these innovations in your own laboratory.

Do you have any highlights from previous conferences. Does anything stand out that was particularly innovative or useful for you?

I first attended the Riva conference in 1989, and have participated in every edition since. Throughout these years, I've come across a range of new topics at Riva such as high-speed capillary gas chromatography (GC), solid phase microextraction (SPME), innovative polar GC phases, supercritical fluid extraction (SFE), selective detection, comprehensive two-dimensional GC, and more. Many advances in mass spectrometry (MS) and advanced data processing were also highly significant. Several of these techniques remain integral to our work today. As an example, we still rely heavily on high-speed GC and SPME in our laboratory. While selective detection and SFE are now less central to our processes, the other developments have profoundly influenced how food analysis is conducted in our laboratory.

You are speaking at the Riva Conference in the GC× GC symposium. What is your talk on and why did you choose this topic?

At this year's GC×GC conference, I will discuss two key benefits of comprehensive GC×GC that I believe are often overlooked. While most recognise GC×GC for its enhanced resolution and greater peak capacity—both valuable in food analysis—a standout advantage is the significantly improved sensitivity of cryo-modulated GC×GC, which can yield enhancements of 10 to 20 times. Furthermore, the second dimension of a GC×GC system essentially operates as a high-speed GC, allowing additional applications. Together with Fulvia Trapani, a student from Prof. Chiaro Cordero’s group in Turin, we have devised a method to use this second dimension independently, enabling rapid tracking of dynamic processes like the release of food flavors during consumption. It is worth noting that my first meeting with Professor Cordero was at Riva years ago, highlighting how networking remains an important reason to attend the event.

How does cryogenic modulation in comprehensive GC×GC lead to a 10–20× increase in sensitivity, and why is this improvement particularly important in food flavour analysis?

In comprehensive GC×GC using cryo-modulation, material is trapped for up to 10 s before it is reinjected as a highly concentrated band into the second dimension. Since the second column is short and separates quickly, peak broadening is minimal. This means the sampled material collected over 10 s is refocused into a band lasting less than a second, resulting in significantly increased concentration and improved sensitivity.

In which situations can GC×GC sensitivity improvements close the gap between instrumental detection limits and human olfactory sensitivity, and where do limitations still remain?

For most food flavors, analytical instruments and the human olfactory system demonstrate comparable sensitivity. However, certain compounds exhibit greater detectability by the nose. These substances often remain undetected by current instrumentation. Enhancing the sensitivity of GC–MS systems by a factor of 10 to 20 would substantially decrease that number of undetected compounds. Still, some compounds would still be beyond detection, even with a 100-fold increase in sensitivity. Therefore ongoing advancements in this area are necessary.

How can the high-speed separation capability of the second GC dimension be exploited to monitor rapid flavour-release events such as chewing-induced bursts?

Our perception of food flavor is influenced not only by the flavor itself, but also by how it is released as we eat. A strong initial burst of flavor can leave a lasting positive impression. This makes understanding how flavors are released in the mouth essential. However, it's quite challenging to measure flavor release directly in the mouth. In the food industry, we often use an artificial mouth setup—a stirred container with artificial saliva—where we place a spoonful of food. By using high-speed gas chromatography (GC), we can track how flavors are released and determine if certain compounds are liberated faster than others. When trying to mask unwanted tastes, it’s crucial that both the pleasant masking flavor and the off-flavor have similar release profiles. All these processes can be explored using the artificial mouth and rapid GC analysis, which helps us avoid costly, time-consuming, and subjective human tasting panels.

What are the analytical and practical advantages of temporarily removing the first GC dimension and using the instrument as a fast GC system for time-resolved measurements?

Few people realise that when using comprehensive GC×GC, they also have access to a high-speed GC. The second dimension of a GC×GC instrument functions as a fast GC, capable of achieving separations in 10 seconds or less. Employing your GC×GC instrument as a fast GC is straightforward: simply replace the first-dimension column with a transfer line. To revert back to GC×GC mode, remove the transfer line and reinstall the column. In practice, the impact of these changes is quite limited.

How does combining cryogenic focusing with rapid second-dimension analysis enable experiments such as artificial mouth simulations to study flavour release dynamics in real time?

The average residence time of a food product in the mouth is typically under one minute. To accurately characterize the release profile of a flavor within this timeframe, it is necessary to perform approximately 5 to 10 measurements during this period, requiring sampling intervals of every 6 to 12 s. In order to achieve the desired sensitivity, enrichment is advantageous. The modulator and second dimension of a GC×GC instrument facilitate this process: the modulator enriches the sample, while the second dimension provides rapid separation.

Is GC×GC becoming more practical in routine analysis. If so, in what applications?

GC×GC is a practical method that trained personnel can use in any lab. The equipment is dependable, and the accompanying software is user-friendly. Naturally, a GC×GC system is pricier and more complex than standard GC instruments. In our laboratory, we reserve comprehensive GC for cases when maximum resolution or sensitivity is essential. Whenever we receive a new sample that requires thorough analysis, we first run it on our GC×GC instrument. If the enhanced resolution and sensitivity aren't needed, we switch to a regular one-dimensional GC–MS for further work. One major advantage of GC×GC is that it greatly reduces the risk of overlooking important details in unfamiliar samples. This benefit applies across various fields, including environmental testing, packaging research, and flavor analysis.

Further Information
The 44^th international Symposium on Capillary Chromatography (ISCC) and 21^st GC x GC Symposium takes place from May 17–22 2026 at the Conference Centre, Riva Del Garda, Italy. For more information on the scientific programme and conference events, please go to: https://iscc44.chromaleont.it/