Calibration innovations to enhance the accuracy of proton-transfer-reaction mass spectrometry for volatile organic compounds measurements

Volatile organic compounds (VOCs) detection and analysis techniques are critical for understanding their emissions, transport, and impacts. Proton-transfer-reaction mass spectrometry (PTR-MS) is one of the most widely used methods for real-time monitoring VOCs emissions due to its high time resolution and low detection limits. Quantification of VOCs measurement data must be reliable to ensure data comparability, which heavily depends on measurement uncertainty. In this review, the definition of measurement uncertainty and its importance in VOCs measurements are present. Then, the sources of VOCs measurement uncertainty are discussed, and corresponding methods to reduce it are analyzed. Furthermore, several important innovations in PTR-MS calibration are detailed. These calibration innovations have enhanced the accuracy and efficiency of PTR-MS measurements. This review presents a recent calibration approach developed by the National Physics Laboratory (NPL) and the University of Utrecht, considered the most pragmatic for addressing PTR-MS measurement accuracy and comparability. Finally, perspectives for the PTR-MS are suggested: Technologies, such as electronics, optics, chemistry, mechanics, and so on, are anticipated to enhance PTR-MS systems, reduce costs, and increase their popularity.