Agarwal Bishu, González-Méndez Ramón, Lanza Matteo, Sulzer Philipp, Märk Tilmann D, Thomas Neil, Mayhew Chris A
IONICON Analytik Gesellschaft m.b.H. , Eduard-Bodem-Gasse 3, A-6020 Innsbruck, Austria.
J Phys Chem A. 2014 Sep 18;118(37):8229-36. doi: 10.1021/jp5010192. Epub 2014 Mar 17.
We have investigated the reactions of NO(+), H3O(+), O2(+), and Kr(+) with picric acid (2,4,6 trinitrophenol, C6H3N3O7, PiA) using a time-of-flight mass spectrometer with a switchable reagent ion source. NO(+) forms a simple adduct ion PiA·NO(+), while H3O(+) reacts with PiA via nondissociative proton transfer to form PiAH(+). In contrast, both O2(+) and Kr(+) react with PiA by nondissociative charge transfer to produce PiA(+). For Kr(+), we also observe dissociation of PiA, producing NO2(+) with a branching percentage of approximately 40%. For the reagent ions H3O(+) and O2(+) (and operating the drift tube with normal laboratory air), we find that the intensities of the PiAH(+) and PiA(+) ions both exhibit a peak at a given drift-tube voltage (which is humidity dependent). This unusual behavior implies a peak in the detection sensitivity of PiA as a function of the drift-tube voltage (and hence E/N). Aided by electronic-structure calculations and our previous studies of trinitrotoluene and trinitrobenzene, we provide a possible explanation for the observed peak in the detection sensitivity of PiA.
我们使用带有可切换试剂离子源的飞行时间质谱仪，研究了NO(+)、H3O(+)、O2(+)和Kr(+)与苦味酸（2,4,6-三硝基苯酚，C6H3N3O7，PiA）的反应。NO(+)形成简单的加合离子PiA·NO(+)，而H3O(+)通过非解离质子转移与PiA反应形成PiAH(+)。相比之下，O2(+)和Kr(+)均通过非解离电荷转移与PiA反应生成PiA(+)。对于Kr(+)，我们还观察到PiA的解离，产生分支百分比约为40%的NO2(+)。对于试剂离子H3O(+)和O2(+)（以及在正常实验室空气中操作漂移管），我们发现PiAH(+)和PiA(+)离子的强度在给定的漂移管电压下（该电压取决于湿度）均呈现出一个峰值。这种异常行为意味着PiA的检测灵敏度随漂移管电压（进而随E/N）呈现出一个峰值。借助电子结构计算以及我们之前对三硝基甲苯和三硝基苯的研究，我们对观察到的PiA检测灵敏度峰值给出了一种可能的解释。
