Cancelled due to the Coronavirus outbreak >> EMPA Lecture Kenneth Marcus
EMPA Lecture Kenneth Marcus - The Liquid Sampling-Atmospheric Pressure Glow Discharge: A Combined Atomic and Molecular (CAM) Ionization Source.
The world of chemical analysis has been divided into two worlds, elemental and molecular, since before the time of the Bünsen burner. Exquisite methods have been developed across the many forms of spectroscopy which have been tailored for the determination of the elemental and molecular species composition (both qualitative and quantitative) of diverse materials. For most sample types, there is the need to affect comprehensive analysis to provide both types of information. Unfortunately, the underlying physics and chemistry preclude the practical existence of singular methods that provide this capability. In the realm of analytical mass spectrometry, there are ionization sources, and indeed mass analyzer systems, that operate exclusively in either the atomic or molecular space; as Kipling said “never the twain shall meet”. At least until now. This laboratory, in collaboration with the Pacific Northwest National Laboratory, has developed the liquid sampling-atmospheric pressure glow discharge (LS-APGD) as a highly versatile ionization source. Early efforts focused first on elemental analysis, with the potential power of the approach towards isotope ratio mass spectrometry (IRMS) best demonstrated in the coupling of the microplasma with an array of Orbitrap mass analyzers. While never suggested as a strong suit of that organic MS, the combination of the known high-resolution capabilities, with the inherent multiplex advantages found in Fourier transform (FT) processing, yields surprisingly high levels of IR precision and accuracy. Implementation of novel time domain acquisition and processing capabilities (Spectroswiss Booster) provides benefits beyond standard Orbitrap systems. Beyond the more-widely demonstrated atomic MS capabilities (akin to ICP-MS), the same ionization source can be operated to yield molecular mass spectra that are reminiscent of those derived from atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) from species ranging from low molecular weight pharmaceuticals to proteins and organometallic complexes. Thus, the LS-APGD microplasma is a combined atomic and molecular (CAM) ionization source. Toggling between the atomic and molecular spectra production modes can be affected by either changes in the sustaining electrolye/carrier solutions or by changing plasma operation regimes. In the first case, atomic mass spectra are derived when 2% HNO3 is used as the electrolyte, while mixed solvents (H2O:methanol:acetonitrile) provide a strong proton transfer environment. The differences in spectral character will be presented. A newly designed set of electrode geometries provides a means of operating the plasma using a single solvent, by toggling the energy input to the plasma. Thus, the spectral characteristics can be modulated on sub-second time scales. The latter approach is seen as a key development in terms of affecting CAM-MS in the scope of liquid chromatography separations. It is believed that the concept of CAM-MS, affected on more widely-available organic MS platforms, may open up totally new approaches to comprehensive chemical analysis.
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IMSC travel award
5 Postgraduate Awards
• 5 awards of €1200 will be made to assist the awardees in travel and attendance at the
• Each winner will receive a complimentary subscription to the Journal of Mass
• The postgraduate student winners will include representatives from Europe/Africa, Asia/
and the Americas.
• Each winner will present a 15-minute oral presentation on their work in the JMS Awards
• Each winner will receive a certificate and mention in the Journal and have the opportunity
to publish their paper in the journal if they choose.