Development of a simultaneous analysis method of volatile compounds by DART MS

Significance of the Topic

Rapid, selective monitoring of aroma-related volatile compounds is essential in food science to link chemical profiles with sensory perception during consumption. Conventional gas chromatography can be time-consuming and often struggles to distinguish structural isomers using selected ion monitoring. Coupling direct analysis in real time (DART) with LC-MS/MS addresses these limitations by enabling near-instantaneous detection and high selectivity.

Objectives and Study Overview

The study aimed to establish a simultaneous analysis method for five structurally similar volatile compounds (γ-terpinene, 1,8-cineol, linalool, limonene, cuminal) by integrating DART-OS with a triple quadrupole LC-MS/MS system. Key goals included optimizing ionization conditions and selecting specific multiple reaction monitoring (MRM) transitions to resolve isomeric overlaps.

Methodology and Instrumentation

Standards of the five volatiles were evaluated under electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). Only APCI produced reliable precursor ions (e.g., m/z 137 for four isomers, distinct ions for cuminal). A Shimadzu LCMS-8030 triple quadrupole mass spectrometer was combined with an IonSense DART-OS source equipped with the Volatimeship delivery option. Flow injection analysis was used to screen multiple product ions at varying collision energies and to refine compound-dependent MRM transitions.

Main Results and Discussion

• ESI failed to ionize target volatiles, while APCI yielded strong precursor signals for all compounds.
• Product ion scans identified characteristic fragments for each analyte, enabling selection of highly specific MRM transitions (e.g., 1,8-cineol: 155→81, 155→137; limonene: 135→107; cuminal: 166→149 positive, 163→119 negative).
• Direct DART-MS analysis with optimized MRM settings produced clear, compound-specific chromatographic peaks without the need for separation.

Benefits and Practical Applications

• Enables rapid (<1 s) real-time profiling of aroma compounds during sensory tests.
• Differentiates structural isomers with minimal sample preparation.
• Applicable for quality control in food and flavor industries.

Future Trends and Potential Applications

Advances in automated sample introduction and data processing may extend this approach to complex matrices and high-throughput screening. Portable MS platforms paired with DART technology could facilitate on-site aroma profiling in production environments.

Conclusion

The integrated DART-OS and LC-MS/MS method delivers fast, selective analysis of structurally similar volatile compounds, overcoming time and specificity limitations of traditional GC-SIM techniques.

References

• No specific literature references were provided in the original document.