Using the Chemical Noise Background in MALDI Mass Spectrometry Imaging for Mass Alignment and Calibration
Using the Chemical Noise Background in MALDI Mass Spectrometry Imaging for Mass Alignment and Calibration
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DOI：
10.1021/acs.analchem.9b04473
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发表时间：
2020-01-07
影响因子：
7.4
通讯作者：
Maass, Peter
中科院分区：
文献类型：
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作者：
Boskamp, Tobias;Lachmund, Delf;Maass, Peter
基质辅助激光解吸/电离质谱成像（MALDI MSI）是一种用于福尔马林固定石蜡包埋（FFPE）组织样本研究的成熟工具，并显示出在临床研究和组织病理学诊断中的应用潜力。然而，这种方法的适用性和准确性在很大程度上取决于所获得的数据的质量，特别是轴向飞行时间（TOF）MSI中的质量不对准仍然是一个严重的问题。我们提出了一种质量比对和重新校准的方法，是专门设计的操作MALDI肽成像数据。所提出的方法利用了在肽成像实验中观察到的特征化学噪声背景的统计特性。通过将这些性质与理论肽质量模型进行比较，估计并校正每个光谱的有效质量偏移。在31个FFPE组织样本的队列上评估该方法，追求统计验证方法以估计相对未对准的减少以及绝对质量准确度的增加。我们的研究结果表明，相对质量精度约为5 ppm，绝对精度约为20 ppm，使用我们的方法是可以实现的。
Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is an established tool for the investigation of formalin fixed paraffin embedded (FFPE) tissue samples and shows a high potential for applications in clinical research and histopathological diagnosis. The applicability and accuracy of this method, however, heavily depends on the quality of the acquired data, and in particular mass misalignment in axial time-of-flight (TOF) MSI continues to be a serious issue. We present a mass alignment and recalibration method that is specifically designed to operate on MALDI peptide imaging data. The proposed method exploits statistical properties of the characteristic chemical noise background observed in peptide imaging experiments. By comparing these properties to a theoretical peptide mass model, the effective mass shift of each spectrum is estimated and corrected. The method was evaluated on a cohort of 31 FFPE tissue samples, pursuing a statistical validation approach to estimate both the reduction of relative misalignment, as well as the increase in absolute mass accuracy. Our results suggest that a relative mass precision of approximately 5 ppm and an absolute accuracy of approximately 20 ppm are achievable using our method.