Peña Quevedo, Alvaro J.

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    Cyclic organic peroxides identification and trace analysis by Raman microscopy and open-air chemical ionization mass spectrometry
    (2009) Peña Quevedo, Alvaro J.; Hernández Rivera, Samuel P.; College of Arts and Sciences - Sciences; Cádiz García, Mayra E.; Mina Camilde, Nairmen; Rivera Montalvo, Luis A.; Román Velazquez, Félix R.; Department of Chemistry; Rinaldi, Carlos
    The persistent use of cyclic organic peroxides in explosive devices has increased the interest in study these compounds. Development of methodologies for the detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has become an urgent priority. However, differences in physical properties between cyclic organic peroxides make difficult the development of a general method for peroxide analysis and detection. Following this urgency, the first general technique for the analysis of any peroxide, regarding its structural differences is reported. Characterization and detection of TATP and HMTD was performed using an Open-Air Chemical Ionization High-Resolution Time-of-Flight Mass Spectrometer. The first spectrometric analysis for tetramethylene diperoxide dicarbamide (TMDD) and other nitrogen based peroxides using Raman Microscopy and Mass Spectrometry is reported. Analysis of cyclic peroxides by GC-MS was also conducted to compare results with OACI-HRTOF data. In the OACI mass spectrum, HMTD showed a clear signal at m/z 209 MH+ and a small adduct peak at m/z 226 [M+NH4] + that allowed its detection in commercial standard solutions and lab made standards. TMDD presented a molecular peak of m/z 237 MH+ and an adduct peak of m/z 254 [M+NH4] + . TATP showed a single peak at m/z 240 [M+NH4]+ , while the peak of m/z 223 or 222 was completely absent. This evidence suggests that triperoxides are stabilized by the ammonium ion. TATP samples with deuterium enrichment were analyzed to compare results that could differentiate from HMTD. Raman microscopy was used as a complementary characterization method and was an essential tool for cyclic peroxides identification, particularly for those which could not be extensively purified. All samples were characterized by Raman spectroscopy to confirm the Mass Spectrometry results. Peroxide O-O vibrations were observed around 750-970 cm-1. D18-TATP studies had identified ketone triperoxide ν(O-O) vibration around 875 cm-1 in Raman. HMTD and TMDD shared ν(O-O) vibration around 912 cm-1(HMTD: 910 cm-1; TMDD: 914 cm-1). Some of the vibrations identified were v(CH){3000-2930 cm-1}, ν(C-O){1000-1100 cm-1}, δ(CH-C){1470-1400 cm-1}, ν(N-C){1370 cm-1}, and ν(N-H){3340 cm-1}. Both Raman microscopy and OACI-mass spectrometry represent excellent alternatives to be used sensitive checkpoints and forensic laboratories.