Characterization of APi-ToF-CIMS Sensitivity to Multifunctional Organic Molecules at EUPHORE Chambers

We conducted a series of tests using the FIGAERO-HR-ToF-CIMS to assess its sensitivity to a diverse array of multifunctional organic molecules. These experiments were conducted under dark conditions in the 200 m³ outdoor chambers at EUPHORE, ensuring nearly stable concentrations of the studied compounds within a controlled environment.

 

The goal of these tests was to characterize the state-of-the-art instruments I-HR-ToF-CIMS coupled with the FIGAERO inlet, which allows both gas and particle phase analysis. It aimed at exploring the limits of the instruments, optimizing their performance, and ensuring the quality of their data. A series of compounds at nearly stable concentrations were measured under a range of declustering conditions, determined by the voltage settings in the transfer stages between the ion molecule reactor (IMR) and the ToF region. The concentration of the compounds was quantified using the FTIR and PTR-TOF-MS techniques.

 

These tests comprised two types: one involving the introduction of compounds into the chamber and another derived from biomass burning experiments. The relationship between the “dV50” and the sensitivity has been explored. Overall, higher dV50 values were observed compared to the consulted literature (Lopez-Hilkfiker et al. 2016), demonstrating the importance of characterizing each individual instrument. These results are connected to a series of compounds, among which formic acid, nitric acid, and propionic acid are included, that we aim to expand on to better understand the instrument's sensitivity. This instrumental characterization is contributing to a molecular characterization of gas- and particulate phase biomass burning compounds studied in the EUPHORE chamber.

 

This work is part of a project supported by the European Commission under the Horizon 2020 – Research and Innovation Framework Programme through the ATMO-ACCESS Integrating Activity (H2020-INFRAIA-2020-1) and by the R+D project ATMOBE (PID2022-142366OB-I00), funded by MCIN/AEI/10.13039/501100011033/, the "ERDF A way of making Europe”, the Valencian Regional Government (GVA) and the EVER project (CIPROM/2022/37). EUPHORE is part of the ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure) network. Acknowledgements to the staff members Tatiana Gómez, Maria L. Martínez, and the PhD student Beatriz Domínguez for their collaboration in performing the experiments.

 

References:

Lopez-Hilfiker, F. D., Iyer, S., Mohr, C., Lee, B. H., D'Ambro, E. L., Kurtén, T., and Thornton, J. A.: Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts, Atmos. Meas. Tech., 9, 1505–1512, https://doi.org/10.5194/amt-9-1505-2016, 2016.