MALDI-MS imaging of lipids in corn using a flexible ultrasonic spraying device as matrix deposition method

Pei, Xing-Li; Liu, Xiaoning; Du, Jialin; Gong, Chao; Xu, Xu

doi:10.1016/j.ijms.2020.116373

Cited by 9 publications

(1 citation statement)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In some cases, sample flatness is not enough to prevent mass shift occurring. Indeed, the mode of matrix deposition affects the homogeneity of the matrix crystals [30,31] and may induce mass shift as well. As previously shown in Fig.…”

Section: Sample Thicknessmentioning

confidence: 99%

Mass shift in mass spectrometry imaging: comprehensive analysis and practical corrective workflow

et al. 2021

View full text Add to dashboard Cite

MALDI mass spectrometry imaging (MSI) allows the mapping and the tentative identification of compounds based on their m/z value. In typical MSI, a spectrum is taken at incremental 2D coordinates (pixels) across a sample surface. Single pixel mass spectra show the resolving power of the mass analyzer. Mass shift, i.e., variations of the m/z of the same ion(s), may occur from one pixel to another. The superposition of shifted masses from individual pixels peaks apparently degrades the resolution and the mass accuracy in the average spectrum. This leads to low confidence annotations and biased localization in the image. Besides the intrinsic performances of the analyzer, the sample properties (local composition, thickness, matrix deposition) and the calibration method are sources of mass shift. Here, we report a critical analysis and recommendations to mitigate these sources of mass shift. Mass shift 2D distributions were mapped to illustrate its effect and explore systematically its origin. Adapting the sample preparation, carefully selecting the data acquisition settings, and wisely applying post-processing methods (i.e., m/z realignment or individual m/z recalibration pixel by pixel) are key factors to lower the mass shift and to improve image quality and annotations. A recommended workflow, resulting from a comprehensive analysis, was successfully applied to several complex samples acquired on both MALDI ToF and MALDI FT-ICR instruments.

show abstract

Section: Sample Thicknessmentioning

confidence: 99%