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为了更好的对多级质谱裂解信息进行解析,本研究在多级质谱中应用同位素峰信息进行分子式确证。使用二级质谱中同位素峰丰度比例和峰形信息,对化合物的质谱裂解碎片分子组成进行预测和推断。通过改变LTQ Orbitrap XL仪器的离子阱参数,将isolation width设为6u,使目标母离子的最轻同位素峰和两个较重同位素峰共同裂解,报道了在二级质谱中获得目标化合物的同位素信息,并使用这些信息对化合物裂解碎片进行推测。以磺胺甲基嘧啶为例,通过同位素信息提供的丰度比和峰形信息,对主要裂解碎片离子进行解析,大多数结果与文献报道的裂解途径一致,但对于磺胺甲基嘧啶二级质谱中m/z65的碎片离子,与已发表的文献报道不同,通过高分辨质谱和同位素丰度比的佐证,重新对其进行了解析,证明这是一个不含硫元素的子离子。结果表明,该方法能够有效减少分子式推测过程中产生的错误备选结果,可以为多级质谱的解析提供更准确的依据。
In order to better analyze the multi-level mass spectrometry cleavage information, this study confirmed the molecular formula by using the isotopic peak information in multi-level mass spectrometry. Using the isotopic abundance ratio and peak shape information of secondary mass spectra, the molecular composition of the mass spectral fragmentation of the compounds was predicted and inferred. By changing the ion trap parameters of the LTQ Orbitrap XL instrument and setting the isolation width to 6u, the lightest isotope peak of the target parent ion and the two heavier isotope peaks are co-lysed, and the isotopic information of the target compound obtained in the secondary mass spectrum And using this information to infer the fragmentation of the compound. Taking Sulfamethazine as an example, the major fragment ions were analyzed by abundance ratio and peak shape information provided by isotope information. Most of the results were consistent with those reported in the literature. However, for sulfamerazine pyrimidine two mass spectrometry Different from those reported in the literature, fragment ions of m / z65 were re-analyzed by high-resolution mass spectrometry and abundance ratio of isotopes and proved to be a sulfur ion-free ion. The results show that this method can effectively reduce the wrong candidate results in the molecular speculation process and provide a more accurate basis for the analysis of multi-level mass spectra.