Proton Transfer Reaction Mass Spectrometry Applications in Environmental Monitoring

Proton Transfer Reaction Mass Spectrometry (PTR-MS) has emerged as a cornerstone analytical technique for characterising volatile organic compounds (VOCs) in a broad range of environmental contexts. By employing hydronium ions (H3O+) to ionise gaseous organics via soft proton transfer, PTR-MS delivers rapid, high-sensitivity measurements with minimal fragmentation. Coupled with time-of-flight or quadrupole detectors, it resolves complex mixtures in real time, enabling quantification of hundreds of species at sub-part-per-billion levels. The versatility of PTR-MS spans ambient air monitoring of biogenic and anthropogenic emissions, indoor air quality assessments, plume characterisation during wildfires or industrial incidents, and near-source investigations of reactive organic gases. Its capacity for online, continuous operation supports long-term trend analysis and episodic event studies alike. Recent instrumental refinements—such as enhanced mass resolution, reduced detection limits and integrated thermal-desorption inlets—have extended its application to semi-volatile aerosols and liquid-phase volatilisation. These advances underpin a global research effort to map VOC distributions, evaluate ozone and secondary organic aerosol formation potential, and inform regulatory strategies for air quality management. Practical deployments in urban, rural and remote settings attest to its value for both fundamental atmospheric chemistry and rapid response to environmental crises.

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Proton Transfer Reaction Mass Spectrometry Applications in Environmental Monitoring publication trend

The graph below shows the total number of articles in proton transfer reaction mass spectrometry applications in environmental monitoring across all publications each year (not limited to Nature Index journals).

Technical terms

Proton Transfer Reaction Mass Spectrometry (PTR-MS): An online analytical method using H3O+ reagent ions to ionise and detect volatile organic compounds in the gas phase with high temporal resolution.

Volatile Organic Compounds (VOCs): Organic chemicals that readily evaporate into the atmosphere and contribute to air pollution, photochemical smog and secondary aerosol formation.

Secondary Organic Aerosol (SOA): Particulate matter formed by the atmospheric oxidation of VOCs, which influences air quality, human health and climate.

Reaction rate constant (k_PT): A kinetic parameter defining the speed of proton transfer between the reagent ion and target molecule within the PTR-MS drift tube.

References

1. Measurement report: Underestimated reactive organic gases from residential combustion – insights from a near-complete speciation. Atmospheric Chemistry and Physics (2023).
2. The application of PTR-MS and non-targeted analysis to characterize VOCs emitted from a plastic recycling facility fire. Journal of Exposure Science & Environmental Epidemiology (2024).
3. Proton-transfer rate constants for the determination of organic indoor air pollutants by online mass spectrometry. RSC Advances (2023).