HRMS快速筛查结合NMR表征确证食品基质中一种新型他达拉非衍生物

Structural Elucidation of a Novel Tadalafil Derivative in Food Matrix using HRMS Rapid Screening Combined with NMR Characterization

摘要:

为了筛查宣称具有壮阳功效的保健食品中的新型非法添加那/拉非类化合物，采用超高效液相色谱-高分辨质谱仪快速筛查结合核磁共振波谱仪表征的方法对疑似物进行了确证和检测分析。待检样品用甲醇/水提取后，经稀释进行高分辨质谱快速采样筛查；结合高分辨质谱数据库及异常峰的特征碎片离子进行分析，确认疑似物的类型。通过柱层析分离得到疑似化合物的对照品后，经核磁共振波谱技术表征并解析其分子结构。在疑似化合物二级质谱图中，质荷比为254.0932、226.0984、197.0714和169.0759的特征碎片离子及质荷比248.1080和121.0647的碎片离子表明疑似化合物为N-去甲基他达拉非胡椒环上发生了氧原子离去的化合物。结合1H NMR中3.73 (3H, s)的化学位移值和峰型及13C NMR中化学位移129.31和114.03的峰响应，新型非法添加化合物被确证为去氧去甲基他达拉非，并通过紫外光谱图进行验证。研究采用高效液相色谱法对食品基质中的去氧去甲基他达拉非进行了定量分析，并对去甲基他达拉非和去氧去甲基他达拉非的质谱裂解机理进行了详细的解释，对原子及峰裂分进行了核磁谱图归属，可为保健食品中新型非法添加化合物的快速筛查提供技术支持，为化合物确证提供参考模型。

Abstract:

To screen novel illegally added nafils in health food which claimed to have aphrodisiac effect, an analytical method combining rapid screening by high resolution mass spectrometry (HRMS) and characterization by nuclear magnetic resonance spectroscopy (NMR) was used for confirmation and detection of suspected samples. The sample to be detected was extracted with methanol/water, and diluted for rapid sampling and screening with HRMS. Further combined with the HRMS database and the characteristic fragment ions of abnormal peaks, the types of suspected compounds were confirmed. The reference standard of the suspected compound was separated by column chromatography, and its molecular structure was characterized by nuclear magnetic resonance spectroscopy. In the secondary mass spectrum of the suspected compound, the characteristic fragment ions with mass-to-charge ratio of 254.0932, 226.0984, 197.0714 and 169.0759, and the fragment ions with mass-to-charge ratio of 248.1080 and 121.0647 indicated that the suspected compound was a compound with oxygen atom leaving on the pepper ring of nortadalafil. Combined with the chemical shift value of 3.73 (3H, s) and the peak types in the 1H NMR spectrum as well as the peak intensity of chemical shifts of 129.31 and 114.03 in the 13C NMR spectrum, the novel illegally added compound was confirmed as desoxynortadalafil, which was verified by the ultraviolet spectrum. In this study, the content of desoxynortadalafil in food matrix was quantitatively analyzed by high-performance liquid chromatography. Furthermore, a fragmentation mechanism of nortadalafil and desoxynortadalafil was explained in detail, and the atoms and peak splitting were assigned by NMR, which could provide technical support for the rapid screening of novel illegal additives in health food, and provide reference model for the confirmation of compounds.