三过氧化三丙酮的稳定同位素比值特征研究

Analysis of Stable Isotope Ratios of Triacetone Triperoxide

本研究采用稳定同位素质谱(IRMS)探讨了不同原料、不同工艺合成的三过氧化三丙酮(TATP)的稳定同位素比值特征,所合成TATP的δ^(13)C、δ^(2)H、δ^(18)O值分别为-31.62‰~-27.50‰、-144.09‰~-107.85‰、30.61‰~38.02‰。结果表明,依据稳定同位素特征可区分不同原料、工艺合成的TATP。所合成的TATP碳、氢稳定同位素比值主要受丙酮影响,氧稳定同位素比值主要与过氧化氢有关,酸作为催化剂并未对TATP的稳定同位素比值产生显著影响。随着反应时间的增加,TATP的δ^(13)C值呈增加趋势。本研究结果对调查TATP的来源有重要意义。

Triacetone triperoxide(TATP)explosive is frequently used by criminals because of its high power and easy preparation.Therefore,the traceability analysis of TATP is of great significance for fighting crime and maintaining public safety.The stable isotope ratio mass spectrometry(IRMS)is a high-precision tool for the measurement of stable isotope ratio,which has been widely used in food science,environmental protection,geology,forensic science,and other fields.A few of studies have been reported to apply IRMS to analyze the isotopic ratio of TATP,verifing the feasibility of using IRMS to distinguish TATP from different sources.However,to realize the precise source tracing of TATP,it is necessary to further study the influence of synthetic raw materials and processes on the stable isotope ratio of TATP.To the end,in this work IRMS was used to explore the characteristics of stable isotope ratio of TATP synthesized by different raw materials and processes.We revealed that the values of carbon isotope(δ^(13) C),hydrogen isotope values(δ^(2)H)and oxygen isotope values(δ^(18) O)of TATP ranged from-31.62‰to-27.50‰(SD<0.06‰),from-144.09‰to-107.85‰(SD<2.78‰)and from 30.61‰to 38.02‰(SD<0.5‰),respectively.The variation in carbon and hydrogen isotope values mostly determined by the isotopic composition of the precursor acetone,which was the donor of the carbon atoms and the main donor of hydrogen atoms in TATP.The variation in oxygen isotope values mostly depended on the isotopic composition of the precursor hydrogen peroxide,which was the donor of oxygen atoms in TATP.Significantly,the reaction pathway of TATP synthesized from acetone and hydrogen peroxide was postulated based on the results of IRMS.Moreover,a linear relationship was found for the carbon isotope values of the precursor acetone and TATP.This can be used in forensic investigations to link TATP samples to their corresponding acetone precursors.The linear relationship of the hydrogen isotope values of the precursor acetone and TATP was poor because of the possible hydrogen exchange during the synthesis.Benzoic acid serving as a catalyst has no significant impact on the stable isotope ratios of TATP.However the reaction time has a great influence on the isotopic composition of TATP.With the increasing of reaction time,the reaction yields increased and the carbon isotope values of TATP also increased because of the kinetic isotope effect.These finding are of great significance for investigating the source of TATP at the crime scene.