Atmospheric pressure ionization-ion trap mass spectrometry: Sensitive and selective detection of explosives and toxic compounds
Abstract
Novel methods were developed for the in-situ, sensitive, accurate, robust, selective, and rapid detection of explosives, chemical warfare agent simulants (CWAs) and toxic industrial compounds (TICs). A sample preconcentration/introduction interface, named single-sided membrane introduction fiber introduction mass spectrometry (SS-MIMS-FIMS) was developed allowing the selective preconcentration of trace amounts of explosives and CWAs in air. Novel desorption electrospray ionization (DESI) variants, called reactive-DESI and desorption atmospheric pressure chemical ionization (DAPCI) were developed, allowing the selective and sensitive detection of trace amounts of explosives on ambient surfaces. DESI ionization mechanisms of explosives were elucidated. Complexation reactions between alkali metals and peroxide explosives (TATP, TrATrP and HMTD) were uncovered allowing their sensitive and selective detection in complex matrices and showing retention of non-covalent interactions in the fragment ions after collision induced dissociation. A novel trace detection method, called non-proximate detection, was developed for the trace detection of explosives, CWAs, organic salts, and active ingredients in pharmaceutical drug formulations at distances up to 3 meters from the mass spectrometer. Suppression of selected compounds in mixtures by addition of a reagent gas that competes for the available charge (ion/molecule reactions) was investigated. The first high surface area DESI multiple sprayer was built to allow sampling of total surface areas as large as 72 mm2, as compared to 4 mm2 in typical DESI experiments. The suitability of atmospheric pressure chemical ionization mass spectrometry as sensing instrumentation for the real-time monitoring of low levels of toxic compounds in complex matrices was assessed. A home built dynamic sample preparation system, a new sealed atmospheric pressure ionization source, and ion/molecule reactions were developed for the analysis of toxic compounds.
Degree
Ph.D.
Advisors
Cooks, Purdue University.
Subject Area
Analytical chemistry
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