Proton transfer reaction mass spectrometry: A green alternative for food volatilome profiling

Proton transfer reaction mass spectrometry (PTR-MS) has been developed for the direct, high sensitivity and high time resolution monitoring of volatile organic compounds (VOCs). Although PTR-MS development was not guided by greenness goals, most of its features perfectly fit within the green analytical chemistry (GAC) principles, making PTR-MS an intrinsically green analytical technique. Indeed, in its basic implementation, it does not require solvents or non-renewable carrier gases and, in principle, distilled water, used to feed the source where precursors ions are formed, is the only consumable. Food science and technology and agroindustry are amongst the fields where PTR-MS has been successfully exploited. Here we review and discuss, with emphasis on the GAC requirements, the potential of PTR-MS as a tool for both fundamental research and industrial applications in different food-related themes: i) food consumption and sensory, ii) bioprocess monitoring, iii) traceability, iv) quality control, and v) high-throughput food volatilome phenotyping. The outcome of all these related studies indicates PTR-MS both as a complementary tool to gas chromatographic methods and as a valuable technique when reduced analysis time, high sensitivity and/or on-line measurement are required.