基于特征峰匹配的TOF-MS重叠谱峰分离方法

TOF-MS overlapped peak separation approach based on characteristic peak matching

针对飞行时间质谱仪(TOF-MS)定量分析过程中存在的同质峰干扰问题,提出了一种谱峰分离的处理方法。首先,根据"TOF-MS质量数相近的谱峰,其形态也相似"的特点,通过高斯曲线与质谱数据的相关运算寻找单峰位置,再按照幅度的"择高弃低"原则选择个体单峰,对其进行叠加和归一化处理得到特征峰。然后,由特征峰构建功率谱密度函数,按照最小原则确定重叠峰位置及幅度,从而达到谱峰分离的目的。最后,将本文方法分别与Gaussin匹配法和Lorentzian匹配法进行了仿真比较,当处理对称峰(对称系数δ=0.2)时,这3种方法的效果基本一致,但当处理非对称峰(δ=1.6)时,本文方法的效果明显优于后两者。应用实例结果表明,采用本文方法对实测29 Si和28 Si 1 H重叠谱峰进行分离,可使分离度由0.371提升至0.519,提高39.9%,且能保持谱峰原始形态信息。

In order to solve the mutual interference problem among homogeneous peaks in Time-offlight and Mass Spectrometry（TOF-MS）quantitative analysis,a spectral peak separation method was presented.First,according to the technical characteristics that those spectral peaks with close mass number have close shape,the peak positions were determined by the correlation algorithm between Gaussian curve and the original mass spectrum.Then,the individual single peaks were selected by the principle of＂high amplitudes kept and low amplitudes left＂.The characteristic peak was obtained by stacking and normalization of the single peaks.The power spectral density function was constructed by the characteristic peak,and positions and amplitudes of the overlapped peak were determined in accordance with the minimum principle,thus achieving the overlapped peak separation.The result obtained by the above characteristic peak matching method was compared with the results of Gaussianmatching method and Lorentzian matching method respectively.When dealing with symmetric peaks withδ= 0.2,these results are basically consistent.However,when dealing with asymmetric peaks withδ= 1.6,the effect of characteristic peak matching method is much better than the other two methods.Experimental results show that the presented method can be used to separate the 29 Si and28Si 1 H overlapped peak,the separation resolution is improved from 0.371 to 0.519,while the original shape information of the peeks is maintained.