Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source for Elemental Analysis and Ambient Mass Spectrometry
EMSL Project ID
47518
Abstract
The continued development of a novel low power, low flow "elemental" ionization source for applications in the areas of metallomics and transportable mass spectrometry is proposed. Based on initial studied at EMSL under this program, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been suggested to be an effective ionization source elemental and isotopic mass spectrometric analysis. Very recently, the LS-APGD ion source has been coupled to an ThermoScientific LCQ instrument in the PI's laboratory at Clemson University. As in the case of the EMSL work, the microplasma directly couples to the MS in place of the standard electrospray ionization source. The luminescent microplasma is struck between the surface of the analyte containing solution flowing (<0.1 mL/min) from a 100 ?m inner diameter fused silica capillary and a 2 mm diameter metallic counter electrode. The practical volume of the plasma is ~1 mm3. The operating parameters of the discharge are 10 – 50 mA and 200 – 500 V dc (i.e., <25 W). These values are in stark contrast to inductively-coupled plasma (ICP) sources commonly used in elemental mass spectrometry. These operational characteristics also bode well for applications as elemental ionization sources for transportable mass spectrometry where size, power, and operation simplicity are at a premium.Studies are proposed to update and expand upon the capabilities of the LS-APGD on the ThermoScientific Exactive OrbitrapTM instrument within the Biological Separations and Mass Spectrometry Group at EMSL, under the direction of Dr. David Koppenaal. The implementation of the microplasma on the Orbitrap will proceed by directly replacing the existing ESI source on that instrument. The recent demonstration of the use of the microplasma as an efficient ionization source for "ambient mass spectrometry" will be put into practice. Successful implementation in this manner would yield a valuable complementary set of experimental capabilities (elemental and ambient analyses) that does not exist with current proteomics instruments. In addition, studies are proposed to benchmark the performance of the LS-APGD in a one-to-one basis against a commercial ICP-MS instrument in the EMSL facilities. In this case, the GBC Optimass 9500 orthogonal, time-of-flight ICP-MS will be employed. It is believed that the LS-APGD represents the first viable "miniaturized" alternative to the venerable ICP-MS, and thus would have great potential across a broad range of EMSL programs.
Project Details
Project type
Exploratory Research
Start Date
2012-10-01
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator