A quantitative chemiluminescent assay for analysis of peroxide-based explosives

Abstract

A quantitative chemiluminescent method, enabling indirect identification of the peroxide-based explosives TATP (triacetone triperoxide) and HMTD (hexamethylene triperoxide diamine) has been developed. Treatment of these compounds with acidic solutions produced peroxides, which were transformed into radical derivatives by horseradish peroxidase (HRP) and then quantified by measuring the light emitted during their oxidation of luminol. The method was first developed in the microplate format and later optimized for a portable luminometer, to enable rapid application of the assay directly on site. When the portable luminometer was used each analysis took only 5-10min. The method had good selectivity, sensitivity, and reproducibility; in the microplate format the limits of detection (LOD) and quantification (LOQ) were 40 and 50ng mL(-1), respectively, for both TATP and HMTD. When the portable luminometer was used the LOD and LOQ were 50 and 100ng mL(-1), respectively, for both compounds. Introduction of light emission-enhancing compounds did not improve the analytical performance of the assay. Imprecision (CV values) was always below 10%. Recovery varied rapidly with time, with an average value of 78% after 5min. No false-positive result was detected on measurement of a variety of samples; this is an important feature for analysis on site. The method was applied both to contaminated materials and to fortified soil samples, simulating operational conditions.