Determining specific food volatiles contributing to PTR-MS ion profiles using GC-EI-MS

Area of Science:

• Analytical Chemistry
• Food Science
• Mass Spectrometry

Background:

• Volatile compounds significantly impact food aroma and quality.
• Accurate identification of these compounds is crucial for food product development.
• Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and Gas Chromatography-Mass Spectrometry (GC-MS) are powerful analytical techniques.

Purpose of the Study:

• To develop and validate an interface connecting PTR-MS and GC-MS for simultaneous analysis of volatile compounds.
• To identify specific volatile compounds contributing to the headspace mass spectra of food products.
• To assess the performance and limitations of the integrated PTR-MS/GC-MS system.

Main Methods:

• Development of an interface between PTR-MS and GC-MS via an existing sniffing port.
• Online analysis of volatile compounds from a model system (hexanal) and a real food system (cheese crackers).
• Utilized purge and trap method for volatile isolation from food samples.

Main Results:

• Demonstrated good linearity (R(2) = 0.88) and correlation between PTR-MS and GC-MS responses for hexanal.
• Successfully assigned most PTR-MS masses to major volatile compounds in cheese crackers.
• Identified challenges including GC resolution, EI-MS identification, PTR-MS sensitivity, and inlet requirements.

Conclusions:

• The developed PTR-MS/GC-MS interface is a viable tool for identifying volatile compounds in complex food matrices.
• The system allows for the assignment of PTR-MS masses to specific volatile compounds, aiding aroma analysis.
• Acknowledged limitations require careful consideration for optimal application and interpretation of results.