FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.
J Am Soc Mass Spectrom. 2023 Jun 7;34(6):1015-1023. doi: 10.1021/jasms.3c00004. Epub 2023 Apr 25.
The collection of profile data is standard practice within the field of mass spectrometry (MS). However, profile data collection often results in large data files that require extensive processing times, especially in mass spectrometry imaging (MSI) studies where thousands of high-resolution scans are recorded. Natively collecting centroid MS data is an alternative that effectively reduces both the resulting file size and the data processing time. Herein, high-resolution accurate mass (HRAM) Orbitrap MSI data on mouse liver tissue sections without automatic gain control (AGC) were natively collected in both profile and centroid modes and compared based on the file size and processing time. Additionally, centroid data were evaluated against the profile data with regard to the spectra integrity, mass measurement accuracy (MMA), and the number of lipid annotations to ensure that centroid data did not compromise the data quality. For both native and postacquisition centroided data, the variation in mass measurement accuracy decreased relative to the profile data collection. Furthermore, centroid data collection increased the number of METASPACE database annotations indicating higher sensitivity and greater accuracy for lipid annotation compared to native profile data collection. Profile MSI data was shown to have a higher likelihood of false positive identifications due to an increased number of data points on either side of the peaks, whereas the same trend was not observed in data collected in native centroid data collection. This publication explores and explains the importance in properly centroiding MSI data, either natively or by adequate centroiding methods, to obtain the most accurate information and come to the best conclusions. These data support that natively collecting centroid data significantly improves MMA to sub-ppm levels without AGC and reduces false positive annotations.
谱图数据的采集在质谱（MS）领域是标准做法。然而，谱图数据的采集通常会产生大量的数据文件，这些文件需要大量的处理时间，尤其是在质谱成像（MSI）研究中，需要记录数千个高分辨率的扫描。直接采集质心 MS 数据是一种有效的替代方法，可以有效减小生成文件的大小和数据处理时间。本文介绍了一种在没有自动增益控制（AGC）的情况下，直接在谱图和质心模式下采集高分辨率精确质量（HRAM）Orbitrap MSI 数据的方法，并基于文件大小和处理时间对两种模式进行了比较。此外，还针对谱图数据评估了质心数据的光谱完整性、质量测量精度（MMA）和脂质注释数量，以确保质心数据不会影响数据质量。对于原始和采集后的质心数据，质量测量精度的变化相对于谱图数据采集有所降低。此外，质心数据采集增加了 METASPACE 数据库注释的数量，表明与原始谱图数据采集相比，脂质注释的灵敏度更高，准确性更好。由于峰两侧的数据点数量增加，谱图 MSI 数据更有可能出现假阳性鉴定，而在原始质心数据采集时则没有观察到这种趋势。本文探讨并解释了正确质心化 MSI 数据（无论是直接质心化还是通过适当的质心化方法）的重要性，以获取最准确的信息并得出最佳结论。这些数据表明，直接采集质心数据可以显著提高 MMA 至亚 ppm 水平，同时无需 AGC，并减少假阳性注释。
