Performance Evaluation of an In-Injection Port Thermal Desorption/Gas Chromatographic/Negative Ion Chemical Ionization Mass Spectrometric Method for Trace Explosive Vapor Analysis

Abstract

A gas chromatographic method utilizing thermal desorption of Tenax TA and sol-gel sorbent traps has been developed and validated for the analysis of trace explosive vapor with negative ion chemical ionization mass spectrometric detection. Sorbent tubes were packed with Tenax TA and sorbent particles prepared in-house by the sol-gel process. Thermal desorption was performed within a split/splitless injection port with minimal instrument modification. Performance was characterized by relative thermal desorption recovery, precision (reproducibility), linearity of the calibration, and method detection limits. Method validation was performed with a series of dinitrotoluenes, dinitrobenzene, trinitrotoluene, trinitrobenzene, two aminodinitrotoluenes, three nitroesters, and two nitramines. The performance of Tenax TA and the sol-gel sorbents is evaluated based on the method validation data. The method was applied to the analysis of trace explosive vapor collected and concentrated with sol-gel solid sorbent traps from the headspace of a smokeless gunpowder sample.

Trace determination of airborne polyfluorinated iodine alkanes using multisorbent thermal desorption/gas chromatography/high resolution mass spectrometry

“…For the positive identification of the analytes of interest, important confirmation criteria published elsewhere [29,34] was utilized for the analysis. Briefly, the retention time of analytes in real samples have to match that of the standards within 5 s. Chemicals positively identified in real samples with signal-to-noise ratio (S/N) greater than 10:1.…”

“…Moreover, many important perfluorinated iodine alkanes and telomer homologues were not included in the mentioned work, and thus a robust analytical method is still unavailable for this purpose. Adsorption/thermal desorption method is generally recognized and widely used as an effective technique for the analysis of a wide range of hazardous air pollutants [26][27][28][29][30] that are classified as volatile organic compounds (VOCs) and usually have vapor pressures above 0.1 Torr [27]. Compared with typical solvent-based extraction and injection scenarios, thermal desorption method requires less pretreatment procedures, reduces mass loss before quantification and enhances detection sensitivity by whole sample injection into the analytical instrument.…”

Nitramine anion fragmentation: A mass spectrometric and Ab initio study

“…Analytical methods based on GC/MS with NCI offer sensitivity similar to that based on GC/ECD but yield more structural information. GC/MS and NCI have previously been used to analyze RDX [31,32], but no mechanistic studies of the ion formation processes for this compound have been carried out to date.…”

Minimizing thermal degradation in gas chromatographic quantitation of pentaerythritol tetranitrate

“…Other published laboratory methods for analysis of trace explosive vapors such as trinitrotoluene (TNT) and hexamethylenetetramine (RDX) involve collection on sorbent-filled tubes during active sampling [5][6][7][8][9][10]. The analyte is then thermally desorbed and refocused on a cryogenically cooled gas chromatograph (GC) inlet, followed by gas chromatographic analysis.…”