10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Factors Affecting the Detection of Fine Particles by Secondary Nanoelectropray Ionization High Resolution Mass Spectrometry
Dandan Jin, Anthony S. Wexler, Jiafa Zeng, Man Nin Chan, Zhen Zhou, Yong Jie Li, XUE LI, Jinan University
Abstract Number: 628 Working Group: Instrumentation
Abstract Chemical characterization of aerosol particles at a molecular level is crucial to obtain a better understanding of their impacts on atmospheric chemistry, global climate and human health. Real-time mass spectrometry (MS) based methods have attracted attention due to their merits, which include high time resolution (seconds to minutes), minimization of artifacts resulted from condensation/evaporation during sample pretreatment and avoidance of time-consuming sample pretreatment. Recent studies have indicated that a soft ionization MS technique, secondary/extractive electrospray ionization MS (SESI/EESI-MS) is a promising alternative for the characterization of organic aerosol particles at the molecular level. However, ionization of particle-phase compounds in SESI is quite different from that in gas phase and the procedure is more complicated. Thus, investigations are needed into relevant SESI-MS operating parameters that improve sensitivity, selectivity and user-friendliness. In this study, a secondary nano-electrospray ionization (Sec-nanoESI) source was constructed and coupled with a high resolution quadrupole Orbitrap mass spectrometer (HRMS) for measurements of aerosol phase tartaric acid. Factors affecting the detection of TA particles using Sec-nanoESI-HRMS are systematically investigated and discussed. Temperature of the ion transport tubing (ITT) has the most pronounced impact on ion signal intensity, which may be ascribed to more efficient desolvation and ionization; normalized collision energy (NCE) applied in MS/MS measurement is also a parameter to be tuned to obtain the optimal fragment for quantitative analysis with higher specificity and sensitivity. By using the developed method, high sensitivity (a detection limit of 0.078 µg/m3) and a wide linear range (0–1.686 µg/m3) of TA detection was achieved, providing a proof-of-concept demonstration for our Sec-nanoESI-HRMS in real-time measurements of atmospheric particulate organic matter.