Online Calibration of a Chemical Ionization Mass Spectrometer for Multifunctional Biogenic Organic Nitrates

作者：Michael Robinson, J. M. Roberts, J. A. Neuman, Christopher M. Jernigan, Lu Xu, Matthew M. Coggon, Chelsea E. Stockwell, C. Warneke, Jeff Peischl, J. B. Gilman, Aaron Lamplugh, Andrew W. Rollins, Kristen Zuraski, Jean C. Rivera‐Rios, Yuchen Wang, N. L. Ng, Shang Liu, Steven S. Brown, Patrick R. Veres · 发表于：ACS ES&T Air · 年份：2024 · DOI：10.1021/acsestair.4c00056 · 被引用次数：7 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate、Spectroscopy and Laser Applications

Multifunctional organic nitrates derived from biogenic volatile organic compounds are important for understanding ozone and secondary organic aerosol production from oxidation reactions in the presence of nitrogen oxides. Their measurement is challenging, in part because the quantification of these compounds is difficult and time consuming due to the techniques required to synthesize and purify authentic standards. We describe a novel online synthesis and separation technique and demonstrate its use for calibration of a chemical ionization mass spectrometer using iodide reagent ions (I – CIMS) to measure four isomers of isoprene hydroxy nitrate (IHN; C 5 H 9 NO 4 ), two isomers of methyl vinyl ketone hydroxy nitrate (MVKHN; C 4 H 7 NO 5 ), and four isomers of monoterpene hydroxy nitrate (MTHN; C 10 H 17 NO 4 ). We further apply our separation technique to an isoprene + NO 3 + HO 2 online reactor to calibrate for six isomers of isoprene hydroperoxide nitrate (C 5 H 9 NO 5 ). We find a large range of detection sensitivities and ion molecule reactor (IMR) temperature dependencies among the reported analytes measured as iodide (I – ) clusters. We report a wide range of normalized sensitivities (normalized Hz pptv –1; nHz pptv –1 ) normalized by the [I·H 2 O] − reagent ion signal for this class of analytes (0.2–82 nHz pptv –1 ). The (4,3)-MVKHN isomer is exceptional for its high sensitivity with this ion chemistry (82 ± 5 nHz pptv –1 ), which can lead to an inaccurate representati...