Liquid chromatography—Post-column photochemical conversion and electrochemical detection for determination of peroxide-based explosives

Abstract

SummaryA quantitative trace analysis method for peroxide-based explosives is described. This method uses reversed-phase high-performance liquid chromatography with post-column UV irradiation and electrochemical detection for analysis of triacetonetriperoxide (TATP) and hexamethylenetriperoxide diamine (HMTD). The analytes are initially separated and subsequently decomposed photochemically to hydrogen peroxide, which is finally determined by electrochemical detection. Parameters of the method were optimized for lowest detection limits and fast separation. The limits of detection were 3 x 10-6 M for both TATP and HMTD, respectively. This detection scheme is significantly easier to use than earlier methods applying photochemical decomposition, enzymatic post-column reaction and fluorescence detection for analysis of peroxide-based explosives.

Electrochemical Sensing of Explosives

“…Nanomolar detection limits were observed following short (15 s) irradiation times. An electrochemical detection of TATP and HMTD was also developed by Karsts group, involving liquid-chromatographic separation coupled to a post-column UV irradiation step and amperometric detection of the liberated peroxide [10].…”

Development and Characterization of a Monoclonal Antibody against Triacetone Triperoxide

“…7,8 Another method utilizes UV irradiation to decompose TATP to hydrogen peroxide, which is subsequently detected by the peroxidase-catalyzed formation of the green radical cation 2,2¤-azinobis(3-ethylbenzothiazoline)-6-sulfonate (ABTS). 9 Although portable spectroscopic instrumentation for both Fourier transform infrared (FTIR) and Raman spectroscopy is readily available, one study that has been published so far describes the use of a fiber-optically coupled FTIR for the determination of TATP.…”

The Development of High Performance Liquid Chromatography Systems for the Analysis of Improvised Explosives

“…and 7.27. Given that previous researchers have been able to detect HMTD using electrochemical (65) or fluorescence (58) detection only by first degrading the material into hydrogen peroxide, it is unlikely that any of the peaks that were seen in the present analysis actually correspond to intact HMTD. Rather, these peaks most likely correspond to impurities remaining from the synthesis of the HMTD, such as reaction by-products or leftover starting material.…”

“…Nonetheless, coulometric detectors have been utilized in the detection of TATP and HMTD (65). There are a variety of reference and working electrode combinations that may be employed in amperometric detection.…”

“…Because of problems with the reduction of dissolved oxygen in the mobile phase at this potential, as well as the difficulty in finding a working electrode which can handle such strongly positive potentials, detection of hydrogen peroxide is much more effective when performed in oxidative mode (65).…”