Development of the Molecular Ionization Desorption Analysis Source (MIDAS) for Mass Spectrometry
Loading...
Links to Files
Permanent Link
Collections
Author/Creator
Author/Creator ORCID
Date
2016-01-01
Type of Work
Department
Chemistry & Biochemistry
Program
Chemistry
Citation of Original Publication
Rights
This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu
Distribution Rights granted to UMBC by the author.
Distribution Rights granted to UMBC by the author.
Abstract
Ambient mass spectrometry represents a subset of mass spectrometry in which analytes are ionized and sampled in their native environment with little to no sample preparation. While there are numerous ionization techniques categorized as ambient, this work has focused on (1) studying the ionization phenomenon associated with a commercial Desorption Atmospheric Pressure Chemical Ionization (DAPCI) source, known as Direct Sample Analysis (DSA), through the use of schlieren photography (2) developing new ionization platform, known as the Molecular Ionization Desorption Analysis Source (MIDAS) based on the results of the schlieren study and observations made about the limitations of the original device (3) using various applications to illustrate the capabilities of the new source. Water cluster ion intensity and distribution is affected by source conditions in Direct Sample Analysis (DSA) ionization. Parameters investigated include source nozzle diameter, gas flow rate, and source positions relative to the mass spectrometer inlet. Smaller nozzle diameters and higher flow rates produced clusters of the type [H + (H2O)n]+ with greater n and higher intensity than larger nozzles and lower gas flow rates. At high gas flow rates, the gas flow profile widened compared to the original nozzle diameter. At lower flow rates, the amount of expansion was reduced, which suggests that lowering the flow rate may allow for improvements in sampling spatial resolution. From the results of the schlieren study a new ionization platform was developed. The MIDAS uses DAPCI and a system of interchangeable sampling plates that allow for the rapid analysis of a variety of different compounds from different surfaces. Illustrative applications include analysis of compounds from thin-layer chromatography plates including amino acids and compounds extracted from analgesic tablets. Additionally, ? and ? acids extracted from hop pellets were successfully separated and detected using thin-layer chromatography and MIDAS. Additional applications include the direct analysis of pharmaceutical and nutraceutical tablets, inks, polymers and high throughput analysis of a variety of compounds using 96 well and 384 spot plates.