TATP的质子转移反应的质谱研究

Proton Transfer Reaction Mass Spectrometry of Triacetone Triperoxide

利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/mol,TATP与H3O+可发生质子转移反应.在自行研制的质子转移反应质谱(Proton transfer reaction mass spectrometry,PTR-MS)装置上,研究了TATP与H3O+反应生成的特征离子.当漂移管中E/N=1.4×10-15V.cm2时,在荷质比m/z=91,75,74,59,43等处观察到了产物离子.降低E/N至0.5×10-15V.cm2后,在m/z=223处观察到了质子化产物离子([TATP+H]+),验证了计算结果;结合[TATP+H]+的构型,分析了TATP质子转移反应产物离子可能的归属及其形成过程.结合PTR-MS漂移管内E/N的改变引起m/z=223,91,43等离子的变化特征,可实现TATP的准确识别和快速定量检测,检测下限达到5.0×10-10mol/L(±50%).

Triacetone triperoxide（TATP） is an easily synthesized explosive. Since the TATP contains no nitro groups and is thermally labile, it is difficult to detect with conventional analytical methods used to determine more established explosives, such as TNT and RDX. In this paper, the calculations were carried out for TATP and its protonated ion using the density functional theory （DFT） method at the B3LYP/cc-pVDZ level. The optimized geometries of TATP and [ TATP ＋ H ]^＋ were obtained. The proton affinity of TATP is 866.73 kJ/ tool based on the calculated total energies of TATP and [ TATP ＋ H]^＋. The reaction between H3O^＋ and TATP were researched in paper with the homemade proton transfer reaction mass spectrometry（PTR-MS）. The ion products were found at mass charge ratio of m/z = 91, 75, 74, 59, 43 and so on. After reducing the E/N across the drift tube, the protonated TATP ion was found at mass charge ratio of m/z = 223. Combined the calculated results, the proposed [ TATP ＋ H ]^＋ fragmentation pathways were discussed. TATP can be identified exactly and detected rapidly by the change of these characteristic ions, such as m/z = 223, 91 and 43. The m/z = 43 product ion can be routinely detected at a TATP concentration of about 5.0 × 10^-10 mol/L（ ± 50%）.