Hexamethylene Triperoxide Diamine Research Articles

Characterizing the gas phase ion chemistry of an ion trap mobility spectrometry based explosive trace detector using a tandem mass spectrometer

A commercial-off-the-shelf (COTS) ion trap mobility spectrometry (ITMS) based explosive trace detector (ETD) has been interfaced to a triple quadrupole mass spectrometer (MS/MS) for the purpose of characterizing the gas phase ion chemistry intrinsic to the ITMS instrument. The overall objective of the research is to develop a fundamental understanding of the gas phase ionization processes in the ITMS based ETD to facilitate the advancement of its operational effectiveness as well as guide the development of next generation ETDs. Product ion masses, daughter ion masses, and reduced mobility values measured by the ITMS/MS/MS configuration for a suite of nitro, nitrate, and peroxide containing explosives are reported. Molecular formulas, molecular structures, and ionization pathways for the various product ions are inferred using the mass and mobility data in conjunction with density functional theory. The predominant product ions are identified as follows: [TNT-H]− for trinitrotoluene (TNT), [RDX+Cl]− for cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), [NO3]− for ethylene glycol dinitrate (EGDN), [NG+NO3]− for nitroglycerine (NG), [PETN+NO3]− for pentaerythritol tetranitrate (PETN), [HNO3+NO3]− for ammonium nitrate (NH4NO3), [HMTD−NC3H6O3+H+Cl]− for hexamethylene triperoxide diamine (HMTD), and [(CH3)2CNH2]+ for triacetone triperoxide (TATP). The predominant ionization pathways for the formation of the various product ions are determined to include proton abstraction, ion-molecule attachment, autoionization, first-order and multi-order thermolysis, and nucleophilic substitution. The ion trapping scheme in the reaction region of the ITMS instrument is shown to increase predominant ion intensities relative to the secondary ion intensities when compared to non-ion trap operation.

Investigation of Isotopic Linkages between Precursor Materials and the Improvised High Explosive Product Hexamethylene Triperoxide Diamine

The results of isotope ratio mass spectrometry (IRMS) on hexamethylene triperoxide diamine (HMTD) and its precursor hexamethylenetetramine (hexamine) is presented. HMTD was prepared from hexamine using several different sources of hexamine under both controlled laboratory conditions and in field experiments that represent the less controlled conditions that are likely to be observed in forensic casework scenarios. Precursor and product carbon isotope δ values consistently fit a linear relationship regardless of precursor or conditions. The magnitude of the isotope fractionation observed is affected by the efficiency of the reaction, with greater yielding reactions giving rise to HMTD with δ values more similar to the precursor material than lower yielding reactions. Nitrogen isotope δ values comparing precursor with product show some linearity when the reaction conditions are carefully controlled; however, results indicate a poor fit with linearity when synthesis conditions are more variable. Despite the greater variation, the HMTD product consistently has a more positive δ value compared with the hexamine precursor. The results observed from these experiments suggest hexamine reacts to form HMTD in a 1:1 ratio. Having prepared multiple HMTD samples from various precursors using a range of experimental conditions, we have observed results that may be useful in forensic investigations of improvised explosive materials.

Sensitivity to friction for primary explosives

The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

Cyclic Organic Peroxides Characterization by Mass Spectrometry and Raman Microscopy

Triacetone triperoxide and hexamethylene triperoxide diamine are among the most used and most studied non-nitro based high explosives. Still, there are other peroxides which do not have reported methods for their detection. Direct Analysis in Real Time is an emerging ambient pressure ionization technique in mass spectrometry (MS). This contribution presents the analysis, characterization and detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) using DART. Although typical experiments are done using helium, adding a small amount of ammonium hydroxide improved the detection limit to 30 ppb. This study also presents the detection and identification of benzoyl peroxide, tricyclopentanone triperoxide and tetramethylene diperoxide dicarbamide (TMDD) by MS and Raman microscopy. TATP showed a single peak at m/z 240.144 [M+NH4]+ with the peaks at m/z 223.118 [M+H]+ or 222.110 [M]+ completely absent. Deuterium enriched (TATP-d18) was analyzed for comparison. These presented a similar peak at m/z 258.267 [TATP-d18 +NH4]+. HMTD showed a peak at m/z 209.078 [M+H]+ and small adduct peak at m/z 226.103 [M+NH4]+ that allowed its detection in standard solution and lab made samples. TMDD showed several peaks with a base peak at m/z 101.033, molecular peak at m/z 237.081 [M+H]+ and a strong ammonium adduct at m/z 254.108 [M+NH4]+. All samples were analyzed by Raman Microscopy in order to characterize them and to confirm the MS results.

A quantitative chemiluminescent assay for analysis of peroxide-based explosives

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.

Detection of Explosives and Related Compounds by Low-Temperature Plasma Ambient Ionization Mass Spectrometry

Detection of explosives is important for public safety. A recently developed low-temperature plasma (LTP) probe for desorption and ionization of samples in the ambient environment ( Anal. Chem. 2008 , 80 , 9097 ) is applied in a comprehensive evaluation of analytical performance for rapid detection of 13 explosives and explosives-related compounds. The selected chemicals [pentaerythritol tetranitrate (PETN), trinitrotoluene (TNT), cyclo-1,3,5-trimethylenetrinitramine (RDX), tetryl, cyclo-1,3,5,7-tetramethylenetetranitrate (HMX), hexamethylene triperoxide diamine (HMTD), 2,4-dinitrotoluene, 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, 2,6-dinitrotoluene, and 4-nitrotoluene) were tested at levels in the range 1 pg-10 ng. Most showed remarkable sensitivity in the negative-ion mode, yielding limits of detection in the low picogram range, particularly when analyzed from a glass substrate heated to 120 °C. Ions typically formed from these molecules (M) by LTP include [M + NO(2)](-), [M](-), and [M - NO(2)](-). The LTP-mass spectrometry methodology displayed a linear signal response over three orders of magnitude of analyte amount for the studied explosives. In addition, the effects of synthetic matrices and different types of surfaces were evaluated. The data obtained demonstrate that LTP-MS allows detection of ultratrace amounts of explosives and confirmation of their identity. Tandem mass spectrometry (MS/MS) was used to confirm the presence of selected explosives at low levels; for example, TNT was confirmed at absolute levels as low as 0.6 pg. Linearity and intra- and interday precision were also evaluated, yielding results that demonstrate the potential usefulness and ruggedness of LTP-MS for the detection of explosives of different classes. The use of ion/molecule reactions to form adducts with particular explosives such as RDX and HMX was shown to enhance the selectivity and specificity. This was accomplished by merging the discharge gas with an appropriate reagent headspace vapor (e.g., from a 0.2% trifluoracetic acid solution).

Development of ambient sampling chemi/chemical ion source with dielectric barrier discharge

The development of a new configuration of chemical ionization (CI)-based ion source is presented. The ambient air containing the gaseous sample is sniffed into an enclosed ionization chamber which is of sub-ambient pressure, and is subsequently mixed with metastable species in front of the ion inlet of the mass spectrometer. Metastable helium atoms (He*) are used in this study as the primary ionizing agents and are generated from a dielectric barrier discharge (DBD) source. The DBD is powered by an AC high-voltage supply and the configuration of the electrodes is in such a way that the generated plasma is confined within the discharge tube and is not extended into the ionization chamber. The construction of the ion source is simple, and volatile compounds released from the bulky sample can also be analyzed directly by approaching the sample to the sampling nozzle. When combined with heated nitrogen or other desorption methods, its application can also be extended to non-volatile compounds, and the consumption for helium can be kept minimum solely for maintaining the stable discharge and gas phase ionization. Applications to non-proximate sample analysis, direct determination of active ingredients in drug tablets and the detection of trace explosive such as hexamethylene triperoxide diamine are demonstrated.

Determination of peroxide-based explosives with copper(ii)–neocuproine assay combined with a molecular spectroscopic sensor

The two members of peroxide-based explosives, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD), can be manufactured from readily accessible reagents, and are difficult to detect by conventional analytical methods. TATP and HMTD were securely synthesized, taken up with acetone, hydrolyzed with 4 M HCl to hydrogen peroxide, the acidic solution containing H(2)O(2) was neutralized, and assayed by the copper(II)-neocuproine spectrophotometric method. The chromophore of the reaction was the Cu(I)-neocuproine chelate responsible for light absorption at 454 nm. The molar absorptivity (epsilon) of the method for TATP and HMTD was 3.45 x 10(4) and 4.68 x 10(4) L mol(-1) cm(-1), respectively. The TATP recovery from a synthetically contaminated loamy clay soil was 91-99%. The colorimetric method was also applied to a Cu(ii)-neocuproine-impregnated polymeric Nafion membrane sensor developed for the first time in this work for peroxide explosive assay. The absorbance-concentration response was perfectly linear, and the limit of detection (LOD) of the procedure for both TATP and HMTD was approximately 0.2 mg L(-1). Neither common soil ions (Ca(2+), K(+), Cl(-), SO(4)(2-), Mg(2+) and NO(3)(-)) at 100-fold amounts nor military-purpose nitro-explosives of TNT, RDX, and PETN at 10-fold amounts interfered with the proposed assay. Active oxygen constituents of laundry detergents (perborates and percarbonates), which normally interfered with the assay, could easily be separated from the analytes by solubility differences. The method was statistically validated against standard reference methods of TiOSO(4) colorimetry and GC-MS.

Detection of Impurities in Organic Peroxide Explosives from Precursor Chemicals

Previous analyses of organic peroxide explosives have focussed on identification of the explosive itself, and were performed using explosive samples synthesized from laboratory-grade precursors. In this work, analytical studies of precursors obtained from retail outlets identified compounds that could be carried over into the explosives as impurities during synthesis. Forensic and intelligence information may be gained by the identification of possible precursor impurities in explosive samples. This hypothesis was tested using triacetone triperoxide and hexamethylene triperoxide diamine prepared from domestically available off-the-shelf precursors. Gas chromatography–mass spectrometry analysis showed that compounds originating from such precursors could be detected in the organic peroxide samples at different stages in their purification. Furthermore, some compounds could also be detected in the residues of samples that had been subjected to thermal initiation.

Determining the Vapor Pressures of Diacetone Diperoxide (DADP) and Hexamethylene Triperoxide Diamine (HMTD)

AbstractThe vapor signature of diacetone diperoxide (DADP) and hexamethylene triperoxide diamine (HMTD) were examined by a gas chromatography (GC) headspace technique over the range of 15 to 55 °C. Parallel experiments were conducted to redetermine the vapor pressures of 2,4,6‐trinitrotoluene (TNT) and triacetone triperoxide (TATP). The TNT and TATP vapor pressures were in agreement with the previously reported results. Vapor pressure of DADP was determined to be 17.7 Pa at 25 °C, which is approximately 2.6 times higher than TATP at the same temperature. The Clapeyron equation, relating vapor pressure and temperature, was LnP (Pa)=35.9−9845.1/T (K) for DADP. Heat of sublimation, calculated from the slope of the line for the Clapeyron equation, was 81.9 kJ mole−1. HMTD vapor pressure was not determined due to reduced thermal stability resulting in vapor phase decomposition products.

Selective and rapid detection of triacetone triperoxide by double-step chronoamperometry

A selective detector for the improvised explosive, triacetone triperoxide is proposed. This is based on the rapid redox reaction of peroxides (hexamethylene triperoxide diamine, benzoyl peroxide, t-butyl peroxide, triacetone triperoxide and H 2O 2) with bromide at 55 °C. Consumption of bromide is indicative of the reduction of the R–O–O–R moiety, the appearance of Br 2 was found for all except for triacetone triperoxide. The latter was found to breakdown to acetone which rapidly reacts with Br 2 producing bromoacetones. The lack of Br 2 production is unique to triacetone triperoxide. Double step chronoamperometry (E 1 = 700 mV, E 2 = 960 mV (vs. Ag/AgCl)) allows for the quantitation of bromine (Br 2 + 2e − ➔ 2Br −) and bromide (2Br − ➔ Br 2 + 2e −) respectively. The results yielded a detection limit of 8.5 µM for triacetone triperoxide with a sensitivity of 0.026 µA µM − 1 . The detection limits of 16.3 µM and 14.9 µM were found respectively for HMTD and H 2O 2 based on the appearance of Bromine. These results indicate a possibility to develop a handheld sensor for TATP dermination.

Destruction of Peroxide Explosives

Chemicals containing multiple peroxide functionalities, such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), or hexamethylene triperoxide diamine (HMTD), can be explosive. They are impractical and are not used by legitimate military groups because they are shock and heat sensitive compared to military explosives. They are attractive to terrorists because synthesis is straightforward, requiring only a few easily obtained ingredients. Physical removal of these synthesis products is highly hazardous. This paper discusses methods to degrade peroxide explosives chemically, at room temperature. A number of mixtures containing metals (e.g., zinc, copper) and metal salts (e.g., zinc sulfate, copper chloride) were found effective, some capable of destroying TATP solutions in a few hours. Strong acids proved useful against solid peroxide materials; however, on a 1 g scale, addition of concentrated sulfuric acid caused TATP to detonate. Thus, this technique should only be used to destroy small-laboratory quantities.

Current trends in the detection of peroxide-based explosives

The increased use of peroxide-based explosives (PBEs) in criminal and terrorist activity has created a demand for continued innovation in the detection of these agents. This review provides an update to a previous 2006 review on the detection of PBEs, with a focus in this report on luminescence and fluorescence methods, infrared and Raman spectroscopy, mass spectrometry, and electrochemical techniques. Newer developments in gas chromatography and high performance liquid chromatography methods are also discussed. One recent trend that is discussed is an emphasis on field measurements through the use of portable instruments or portable assay formats. An increase in the use of infrared spectroscopy and mass spectrometry for PBE analysis is also noted. The analysis of triacetone triperoxide has been the focus in the development of many of these methods, although hexamethylene triperoxide diamine has received increased attention in PBE detection during the last few years.

Sensitive Determination of Hexamethylene Triperoxide Diamine Explosives, Using Electrogenerated Chemiluminescence Enhanced by Silver Nitrate

Sensitive detection and quantification of hexamethylene triperoxide diamine (HMTD), which is one of commonly used explosives by terrorists, was presented on the basis of electrogenerated chemiluminescence (ECL) technology coupled with silver nitrate (AgNO3) enhancement in acetonitrile at a platinum electrode. Upon anodic potential scanning, HMTD irreversibly oxidized at approximately 1.70 V vs Ag/Ag+ (10 mM) at a scan rate of 50 mV/s, and the ECL profile was coincident with the oxidation potential of HMTD in the presence of ruthenium(II) tris(bipyridine) (Ru(bpy)3(2+)) luminophore species, which showed a half-wave potential of 0.96 V vs Ag/Ag+. The addition of small amounts of AgNO3 (0.50-7.0 mM) into the HMTD/Ru(bpy)3(2+) system resulted in significant enhancement in HMTD ECL production (up to 27 times). This enhancement was determined to be largely associated with NO3(-) and was linearly proportional to the concentrations of NO3(-) and Ag+ in solution. Homogeneous chemical oxidations of HMTD by electrogenerated NO3* and Ag(II) species proximity to the electrode were proposed to be responsible for the ECL enhancement. On the basis of cyclic voltammetry (CV) and CV digital simulations, standard potential values of 1.79 V vs Ag/Ag+ (or 1.98 V vs NHE) and 1.82 V vs Ag/Ag+ (or 2.01 V vs NHE) were estimated for Ag(II)/Ag(I) and NO3*/NO3(-) couples, respectively. A detection limit of 50 microM of HMTD was achieved with the current technique, which was 10 times more sensitive than that reported previously, which was based on a high-performance liquid chromatography/Fourier transform infrared (HPLC/FT-IR) detection method.

Electrochemical detection of the explosive, hexamethylene triperoxide diamine (HMTD)

A rapid electrochemical detection scheme for the improvised explosive, hexamethylene triperoxide diamine (HMTD) is demonstrated. This is based on the hydrolysis of HMTD releasing H 2O 2 and the electrochemical redox cycling of Fe II/IIIEDTA via the following scheme: Fe IIIEDTA + e −→Fe IIEDTA Fe IIEDTA + HOOH→Fe IIIEDTA + HO + HO − where FeEDTA is the ethylenediaminetetraacetate complex. Cyclic voltammetric results indicate an electrocatalytic (EC′) mechanism. Mass transport aided chronoamperometry at a carbon disk electrode ( E step = − 400 mV vs. Ag/AgCl) gave a limit of detection of 30 μM (3 S b/ m). Most interestingly, the hydrolysis of HMTD was found to be rapid under mild reaction conditions which was found to be complete, and nearly instantaneously when exposed to a 50/50 (v/v%) water/acetonitrile solution at pH 2.1. This is in contrast with previous investigations that require harsher conditions. Neutralization or further derivatization steps were not necessary as the Fe II/IIIEDTA complex acted as an electron shuttle under these conditions. These results indicate a basis for a fast, one-step, and inexpensive detector for HMTD. Based on the results of a previous study, the simultaneous detection of HMTD with another improvised explosive, triacetone triperoxide is a strong possibility.

Raman and Infrared Fingerprint Spectroscopy of Peroxide-Based Explosives

A comparative study of the vibrational spectroscopy of peroxide-based explosives is presented. Triacetone triperoxide (TATP) and hexamethyl-enetriperoxide-diamine (HMTD), now commonly used by terrorists, are examined as well as other peroxide-ring structures: DADP (diacetone diperoxide); TPTP [3,3,6,6,9,9-Hexaethyl-1,2,4,5,7,8-hexaoxo-nonane (tripentanone triperoxide)]; DCypDp {6,7,13,14-Tetraoxadispiro [4.2.4.2]tetradecane (dicyclopentanone diperoxide)}; TCypDp {6,7,15,16,22,23-Hexaoxatrispiro[4.2.4.2.4.2] henicosane (tricyclopentanone triperoxide)}; DCyhDp {7,8,15,16-tetraoxadispiro [5.2.5.2] hexadecane (dicyclohexanone diperoxide)}; and TCyhTp {7,8,14,15,21,22-hexaoxatrispiro [5.2.5.2.5.2] tetracosane (tricyclohexanone triperoxide)}. Both Raman and infrared (IR) spectra were measured and compared to theoretical calculations. The calculated spectra were obtained by calculation of the harmonic frequencies of the studied compounds, at the density functional theory (DFT) B3LYP/cc-pVDZ level of theory, and by the use of scaling factors. It is found that the vibrational features related to the peroxide bonds are strongly mixed. As a result, the spectrum is congested and highly sensitive to minor changes in the molecule.

In Situ Trace Detection of Peroxide Explosives by Desorption Electrospray Ionization and Desorption Atmospheric Pressure Chemical Ionization

Desorption electrospray ionization (DESI) mass spectrometry is used for the rapid (<5 s), selective, and sensitive detection of trace amounts of the peroxide-based explosives, hexamethylene triperoxide diamine (HMTD), tetracetone tetraperoxide (TrATrP), and triacetone triperoxide (TATP), directly from ambient surfaces without any sample preparation. The analytes are observed as the alkali metal ion complexes. Remarkably, collision-induced dissociation (CID) of the HMTD, TATP, and TrATrP complexes with Na(+), K(+), and Li(+) occurs with retention of the metal, a process triggered by an unusual homolytic cleavage of the peroxide bond, forming a distonic ion. This is followed by elimination of a fragment of 30 mass units, shown to be the expected neutral molecule, formaldehyde, in the case of HMTD, but shown by isotopic labeling experiments to be ethane in the cases of TATP and TrATrP. Density functional theory (DFT) calculations support the suggested fragmentation mechanisms for the complexes. Binding energies of Na+ of 40.2 and 33.1 kcal/mol were calculated for TATP-Na(+) and HMTD-Na(+) complexes, suggesting a strong interaction between the peroxide groups and the sodium ion. Increased selectivity is obtained either by MS/MS or by doping the spray solvent with additives that produce the lithium and potassium complexes of TATP, HMTD, and TrATrP. Addition of dopants into the solvent spray increased the signal intensity by an order of magnitude. When pure alcohol or aqueous hydrogen peroxide was used as the spray solvent, the (HMTD + Na)+ complex was able to bind a molecule of alcohol (methanol or ethanol) or hydrogen peroxide, providing additional characteristic ions to increase the selectivity of analysis. DESI also allowed the rapid detection of peroxide explosives in complex matrixes such as diesel fuel and lubricants using single or multiple cation additives (Na(+), K(+), and Li(+), and NH4(+)) in the spray solvent. Low-nanogram detection limits were achieved for HMTD, TrATrP, and TATP in these complex matrixes. The DESI response was linear over 3 orders of magnitude for HMTD and TATP on paper surfaces (1-5000 ng), and quantification of both peroxide explosives from paper gave precisions (RSD) of less than 3%. The use of pure water and compressed air as the DESI spray solution and nebulizing gas, respectively, showed similar ionization efficiencies to those obtained using methanol/water mixtures and nitrogen gas (the typical choices). An alternative ambient method, desorption atmospheric pressure chemical ionization (DAPCI), was also used to detect trace amounts of HMTD and TATP in air by complexation with gas-phase ammonium ions (NH4(+)) generated by atmospheric pressure ammonia ionization.

The 14N quadrupole coupling in hexamethylene triperoxide diamine (HMTD)

Using high-field NMR, we have determined the magnitude of the nuclear quadrupole interaction in hexamethylene triperoxide diamine (HMTD), the explosive allegedly used in the London bombings of July 2005. The experimental quadrupolar coupling constant, 5.334 MHz, is in good agreement with quantum chemical calculations. The predicted single zero-field transition frequency should lie in a relatively empty part of the (14)N nuclear quadrupole resonance (NQR) spectrum; the spin relaxation rate is reasonably fast.

Thermal Decomposition of Organic Peroxides TATP and HMTD by T‐Jump/FTIR Spectroscopy

AbstractThe thermal decomposition of the peroxides, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) was investigated as a function of pressure, temperature and atmosphere by T‐jump/FT‐IR spectroscopy. In an Ar atmosphere at fast heating rates, the dominant decomposition product of TATP was methane rather than acetone which dominates at slow heating rates. The products of TATP were different in Ar and in air which implies that decomposition occurs primarily in the gas phase. In contrast, the products from HMTD were independent of the surrounding atmosphere implying that it decomposes primarily in the condensed phase. The IR spectra of the decomposition products of HMTD exhibited some dependence on pressure but not on the pyrolysis filament temperature.

‘One-step’ simplified electrochemical sensing of TATP based on its acid treatment

A fast, simple and sensitive electrochemical method for sensing peroxide-based explosives based on their acid treatment is reported. The method relies on the high electrocatalytic activity of Prussian-blue (PB)-modified electrodes towards the acid-generated hydrogen peroxide in the harsh acidic medium (down to pH 0.3) used for releasing hydrogen peroxide. Such effective operation of PB electrochemical sensors in strongly acidic media eliminates the need for an additional neutralization step required in analogous peroxidase-based assays (due to acid-induced enzyme deactivation processes). Factors affecting the efficiency of the acid pre-treatment of triacetone triperoxide (TATP) have been examined and optimized to allow its sensitive measurement down to the 50 ng level within 60 s. Chronoamperometric detection of microgram amounts of solid TATP, following a one-minute acid mixing and placing a 20 microL droplet onto a disposable PB-modified screen-printed electrode is illustrated. Similar results were obtained for the peroxide explosive hexamethylene triperoxide diamine (HMTD). By greatly simplifying the analytical procedure, such an acid-operated "artificial peroxidase" electrocatalytic transducer holds great promise for designing "one-step", user-friendly, miniaturized, cost-effective devices for field screening of peroxide explosives.