April 2009 Meeting Announcement, Delaware Valley Mass Spectrometry Discussion Group
- Topic: "Ambient Surface Sampling and Ionization using a Liquid-MicroJunction Surface Sampling Probe Coupled with Electrospray Ionization or Atmospheric Pressure Chemical Ionization
- Speaker: Gary Van Berkel (Oak Ridge National Laboratory, Oak Ridge, TN)
- Date: Monday, April 13, 2009. 6:30 PM
- Time: Social Hour: 6:30 PM.
Talk: 7:30 PM.
Please RSVP to John Masucci JMASUCCI@PRDUS.JNJ.COM by Thursday April 9th.
- Place: Department of Chemistry, Villanova University (Room 154, Mendel Hall)
A number of different atmospheric pressure (AP) surface sampling/ionization techniques have been introduced over the last several years. These and the established ambient surface sampling and ionization methods can be classified on the basis of the desorption process involved in each technique, and then subcategorized by ionization method. This results in four primary categories: thermal desorption/ionization (e.g., direct analysis in real time (DART)), laser desorption (ablation)/ionization (e.g., AP-MALDI), liquid and gas jet desorption/ionization (e.g., desorption electrospray ionization (DESI), and liquid extraction surface sampling probe/ionization. This last, and less publicized category, has been a focus of significant effort in our group. In liquid extraction surface sampling, a confined liquid stream is brought to a surface through a probe acting as a liquid conduit. The analyte in contact with the liquid is reconstituted or extracted from the surface and carried on to the ionization source. Our emphasis has been on a "liquid microjunction" surface sampling probe (LMJ-SSP) that has been coupled with ESI and APCI, but is capable of being coupled with other liquid introduction ionization sources. The LMJ-SSP forms a 'wall-less' liquid microjunction with the surface to be sampled, and species soluble in the elution solvent are extracted and delivered to the ionization source. I will present the fundamentals regarding the setup and operation of such a sampling probe, present relevant figures of merit, and show illustrative applications including the analysis of inks, dyes, pharmaceuticals and peptides on glass slides and thin layer chromatography plates (TLC), and drugs and metabolites from thin tissue sections.
Gary J. Van Berkel, Distinguished Research Staff and Group Leader for the Organic and Biological Mass Spectrometry Group at Oak Ridge National Laboratory, earned his B.A. in Chemistry from Lawrence University (Appleton, WI) and his Ph.D. in Analytical Chemistry from Washington State University (Pullman, WA). His research focuses on the fundamental aspects of atmospheric pressure ion sources for mass spectrometry and on the novel configuration and application of these ion sources to solve analytical problems. His most notable work over the past decade lead to a elucidation of the electrochemical aspects of electrospray ionization. More recently he and his group have been investigating and developing atmospheric pressure surface sampling/ionization instrumental techniques and methods for high throughput analysis and chemical imaging with mass spectrometry.
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