Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
Anal Chem. 2021 Aug 17;93(32):11268-11274. doi: 10.1021/acs.analchem.1c02245. Epub 2021 Aug 4.
Discrimination of isomers in a mixture is a subject of ongoing interest in biology, pharmacology, and forensics. We demonstrate that femtosecond time-resolved mass spectrometry (FTRMS) effectively quantifies mixtures of -, -, and -nitrotoluenes, the first two of which are common explosive degradation products. The key advantage of the FTRMS approach to mixture quantification lies in the ability of the pump-probe laser control scheme to capture distinct fragmentation dynamics of each nitrotoluene cation isomer on femtosecond timescales, thereby allowing for discrimination of the isomers using only the signal of the parent molecular ion at / 137. Upon measurement of reference dynamics of each individual isomer, the molar fractions of binary and ternary mixtures can be predicted to within ∼5 and ∼7% accuracy, respectively.
异构体在混合物中的鉴别是生物学、药理学和法医学领域的研究热点。我们证明，飞秒时间分辨质谱（FTRMS）可以有效地定量分析-、-和-硝基甲苯的混合物，前两者是常见的爆炸物降解产物。FTRMS 方法在混合物定量方面的主要优势在于泵浦-探测激光控制方案能够在飞秒时间尺度内捕获每个硝基甲苯阳离子异构体的独特碎裂动力学，从而仅使用 / 137 的母体分子离子信号就能对异构体进行区分。在测量每个异构体的参考动力学后，二元和三元混合物的摩尔分数可以分别以约 5%和 7%的精度进行预测。
