Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, USA.
Anal Chem. 2011 Jun 1;83(11):4045-52. doi: 10.1021/ac102973a. Epub 2011 May 3.
Infrared multiple photon dissociation (IRMPD) was used to generate vibrational spectra of ions produced with a direct analysis in real time (DART) ionization source coupled to a 4.7 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The location of protonation on the nerve agent simulants diisopropyl methylphosphonate (DIMP) and dimethyl methylphosphonate (DMMP) was studied while solutions of the compounds were introduced for extended periods of time with a syringe pump. Theoretical vibrational spectra were generated with density functional theory calculations. Visual comparison of experimental mid-IR IRMPD spectra and theoretical spectra could not establish definitively if a single structure or a mixture of conformations was present for the protonated parent of each compound. However, theoretical calculations, near-ir IRMPD spectra, and frequency-to-frequency and statistical comparisons indicated that the protonation site for both DIMP and DMMP was predominantly, if not exclusively, the phosphonyl oxygen instead of one of the oxygen atoms with only single bonds.
采用红外多光子解离（IRMPD）技术，结合实时直接分析（DART）电离源和 4.7T 傅里叶变换离子回旋共振（FT-ICR）质谱仪，生成了离子的振动光谱。在长时间使用注射器泵将化合物溶液引入的情况下，研究了神经毒剂模拟物二异丙基甲基膦酸酯（DIMP）和二甲基甲基膦酸酯（DMMP）的质子化位置。通过密度泛函理论计算生成了理论振动光谱。实验中中红外 IRMPD 光谱与理论光谱的直观比较无法明确确定每个化合物的质子化母体是否存在单一结构或构象混合物。然而，理论计算、近红外 IRMPD 光谱以及频率-频率和统计比较表明，DIMP 和 DMMP 的质子化部位主要（如果不是唯一）是膦酰基氧，而不是仅具有单键的氧原子之一。
