The Bipolar FUSION PTR-TOF Mass Spectrometry Technology
The new bipolar FUSION PTR-TOF technology enables multiple fast switching reagent ions, opening up a wide range of applications without compromising the versatility of this powerful all-in-one analyzer generation. There is no need to change the reactor or hardware. With their simplicity at the push of a button, the bipolar FUSION PTR-TOF instruments are a new benchmark in trace gas analysis for the most challenging demands.
Advantages of Multiple Reagent Ions to Characterize Oxidation and Secondary Organic Aerosol Formation
Proton-transfer-reaction mass spectrometry (PTR-MS) is a well-established technique for the characterization of Secondary Organic Aerosols and their precursors.
Advanced instruments such as the recently introduced FUSION PTR-TOF not only use the proven H3O+ reagent ions for quantitative measurements in a wide range of organic compounds, but also offer additional ionization modes such as NH4+ for soft adduct ionization, which enables the detection of highly oxidized compounds. Complemented by the NO+ and O2+ ionization mode, this instrument enables the detection of the vast majority of organic and inorganic compounds.
Fast reagent ion switching
One of the key advantages of the instrument is the ability to rapidly switch between positive ionization modes within seconds, enabled by the innovative Invion Source. This allows flexible and efficient analysis of a wide range of compound classes simultaneously. The data shown in figure 1 highlight the instrument’s ability to switch rapidly and reproducibly between different ionization modes (O2+, H3O+ and NH4+) as well as between E/N settings for H3O+, enabling efficient multi-mode analysis within short timeframes. Switching between different E/N values enables tailored ionization of different compound classes, resulting in enhancing both sensitivity and selectivity.
Learn more about Invion.
Selective Ionization of Acids with CO3-
The next-generation FUSION PTR-TOF mass spectrometer includes the necessary electronics to enable ionization in negative mode with CO3-, as well as fully automatic switching between positive and negative mode. CO3- ionization provides sensitive and highly selective detection of inorganic acids such as SO2, H2SO4 and HNO3 as well as organic acids like perfluoroalkyl carboxylic acids. It enables a soft ionization process with minimal fragmentation – products like limononic acid, for instance, are detected with high efficiency and virtually no fragmentation. The latter can also be seen very clearly in Figure 2, where the product ions of several acids upon H3O+ and CO3- ionization are compared with each other. Figure 3 shows the switching between CO3- and H3O+ ionization modes simply with the push of a button without any hardware adjustments. Learn more about negative ion modes.
Conclusion
- CO3- is highly selective to the formed acids
- Products like Limononic Acid are effectively captured with virtually no fragmentation
- Sequentially ionizing with H3O+, NH4+, NO+ , and CO3- primary reagent ion modes allows for capturing the complete picture of the SOA formation processes
Learn more about the bipolar FUSION PTR-TOF and read the paper on Ultrahigh Sensitivity PTR-MS Instrument with a Well-Defined Ion Chemistry.
View also the latest SRI Folder for more information about Selective Reagent Ionization for PTR-MS.
