RATIONALE Analytical methods for the detection and identification of half nitrogen mustards (halfNMs), i.e., partially hydrolyzed products of nitrogen mustards (pHpNMs), using silyl derivatives are often associated with low sensitivity and selectivity. In order to overcome these limitations, the derivatization of halfNMs was performed using perfluoroacylation. METHODS Two efficient derivatization techniques using trifluoroacetyl (TFA) and heptafluorobutyryl (HFB) groups were developed for the unambiguous identification of halfNMs. A mass spectral database was generated by performing gas chromatography/electron ionization mass spectrometry (GC/EI-MS) and gas chromatography/positive chemical ionization mass spectrometry (GC/PCI-MS). The fragmentation pathways were studied by tandem mass spectrometry (MS/MS) in both EI and PCI mode. RESULTS The EI-MS spectra of the TFA and HFB derivatives of halfNMs contain intense molecular ions and fragment ions, thus making perfluoroacylation preferable to silylation. In addition, the background-free chromatogram obtained using these derivatives provides unambiguous identification of these compounds in blind samples. The structures of the fragment ions were postulated, and the sources of significant ions were traced by performing MS/MS precursor ion scans. In the PCI-MS spectra, along with the protonated molecule, significant peaks due to neutral losses of HF, HCl, CH3 Cl and CF3 COOH were observed. CONCLUSIONS This is the first report of the elucidation of the fragmentation pathways of perfluoroacyl derivatives of halfNMs. The complementary GC/PCI-MS and GC/PCI-MS/MS data will be helpful in the identification of unknown metabolites in a fast and reliable fashion.

中文翻译：

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半氮芥末全氟酰基衍生物的质谱裂解，通过气相色谱/质谱法检测。

合理的分析方法使用甲硅烷基衍生物检测和鉴定半氮芥（halfNMs），即氮芥的部分水解产物（pHpNMs），其灵敏度和选择性较低。为了克服这些限制，使用全氟酰化进行了HalfNMs的衍生。方法使用三氟乙酰基（TFA）和七氟丁酰基（HFB）基团开发了两种有效的衍生技术，用于半NM的明确鉴定。通过执行气相色谱/电子电离质谱（GC / EI-MS）和气相色谱/正化学电离质谱（GC / PCI-MS）生成质谱数据库。在EI和PCI模式下，通过串联质谱（MS / MS）研究了片段化途径。结果HalfNMs的TFA和HFB衍生物的EI-MS光谱包含强分子离子和碎片离子，因此使全氟酰化比甲硅烷基化更可取。此外，使用这些衍生物获得的无背景色谱图可明确鉴定盲样品中的这些化合物。假定碎片离子的结构，并通过执行MS / MS前驱体离子扫描来追踪重要离子的来源。在PCI-MS光谱中，与质子化分子一起，观察到由于HF，HCl，CH3 Cl和CF3 COOH的中性损失而产生的明显峰。结论这是首次阐明HalfNMs的全氟酰基衍生物的断裂途径。