|Abstract Number: ||620 - 3|
|Author Name: ||R Graham Cooks - Purdue University|
|Session Title: ||Miniature Mass Spectrometers: Reaching the Exponential of the Growth Curve|
|Event Type: ||Symposia|
|Event Title: ||Mini Mass Spectrometers: External Ionization & Interfaces|
|Presider Name:||R Graham Cooks||Co-Author:||Zheng Ouyang|
|Affiliation:||Purdue University||Affiliation:||Purdue University|
|Date: ||Monday, March 18, 2013|
|Start Time: ||02:40 PM (Slot #3)|
|The keys to widespread application of miniature mass spectrometers are (i) ambient ionization, viz. ionization in the open environment without sample preparation (ii) tandem mass spectrometry to allow identification of particular compounds in the ionized mixture and (iii) automated library searching to identify the compounds of interest. Ambient ionization – direct analysis of complex materials without prior sample preparation – is essential if miniature mass spectrometers are to see widespread use as in situ general purpose analytical devices. The virtually instantaneous data provided by ambient ionization means that high throughput is possible. It also means that all experiments with complex materials are done in spite of matrix effects – the effect of the sample matrix on the ionization efficiency of analytes of interest. |
This paper briefly reviews the ambient ionization methods and their characteristics. It goes on to describe two particular spray based ambient methods – DESI and paper spray – and a plasma method, low temperature plasma (LTP) ionization. We show examples of quantitation in ambient ionization and describe how matrix effects are handled by using internal standards/. We also give examples of reactive forms of these ionization methods --- i.e. experiments in which the analyte is derivatized in the course of ionization to maximize signal strengths and minimize matrix effects.
Data from and a description of a portable Mini 12 mass spectrometer fitted with a LTP ion source and a discontinuous atmospheric pressure interface will be described. Improved system performance will be illustrated with data on biofluid analysis for drugs of abuse and for therapeutic drug residues.