EVOQUE - Molecular Echoes of Origin: Integrating Portable GC and QEPAS for Coffee Authentication

Rationale The authentication of coffee origin is becoming increasingly important to ensure product quality, supply chain traceability, and preventing food fraud. Volatile Organic Compounds (VOCs) influence coffee’s aroma and flavor, key indicators of both quality and origin. VOC profiles, shaped by factors like bean variety, geography, climate, and processing, act as chemical “fingerprints” to differentiate coffee sources and detect quality issues like adulteration or improper storage [1-2]. This research is part of the EVOQUE project [3], which aims to develop an advanced, photonic-based sensory system for challenging requirements of VOCs measurements at-line, on-line and in-field . The study focuses on the development of a portable platform combining gas chromatography (GC) with quartz-enhanced photoacoustic spectroscopy (QEPAS), quantum cascade lasers, and mid-infrared metasurfaces for high-sensitivity VOCs detection [4]. The system merges GC’s separation capabilities with QEPAS’s selectivity, enabling reliable VOCs analysis in complex food samples, directly in the field or near production. However, challenges include the need for nitrogen as a carrier gas, high flow rates, limited temperature range, and restricted data acquisition speed. Methods The development process focuses on system integration, component optimization and analytical method design to support real-time, non-destructive analysis suitable for field deployment. To do this a method translation strategy starting from conventional GC conditions for coffee origin authentication was applied testing various column geometries to identify optimal configuration to couple with the detector. At the same time high-resolved transmission FTIR spectra of known VOCs in mixtures at the vapor phase was tested to select most selective fingerprint optical features for key analytes and determine the set of laser wavelengths and chips to be produced. Results: Preliminary results indicate the potential of the approaches to distinguish coffee samples from different regions/origins. Once fully realized, the platform is expected to provide a compact, reliable and lab-independent origin authentication solution that supports quality control and transparency throughout the coffee supply chain in line with the principles of Green Analytical Chemistry.