Automated spraying devices have become ubiquitous in laboratories employing matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), in part because they permit control of a number of matrix application parameters that can easily be reproduced for intra- and interlaboratory studies. Determining the optimal parameters for MALDI matrix application, such as temperature, flow rate, spraying velocity, number of spraying cycles, and solvent composition for matrix application, is critical for obtaining high-quality MALDI-MSI data. However, there are no established approaches for optimizing these multiple parameters simultaneously. Instead optimization is performed iteratively (i.e., one parameter at a time), which is time-consuming and can lead to overall nonoptimal settings. In this report, we demonstrate the use a novel experimental design and the response surface methodology to optimize five parameters of MALDI matrix application using a robotic sprayer. Thirty-two combinations of MALDI matrix spraying conditions were tested, which allowed us to elucidate relationships between each of the application parameters as determined by MALDI-MS (specifically, using a 15 T Fourier transform ion cyclotron resonance mass spectrometer). As such, we were able to determine the optimal automated spraying parameters that minimized signal delocalization and enabled high MALDI sensitivity. We envision this optimization strategy can be utilized for other matrix application approaches and MALDI-MSI analyses of other molecular classes and tissue types.

中文翻译：

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响应面方法作为寻找质谱成像最佳 MALDI 基质喷涂参数的新方法。


自动喷雾装置在采用基质辅助激光解吸/电离质谱成像 (MALDI-MSI) 的实验室中已变得无处不在，部分原因是它们可以控制许多基质应用参数，这些参数可以轻松地在实验室内和实验室间研究中重现。确定 MALDI 基质应用的最佳参数，例如温度、流量、喷雾速度、喷雾循环次数和基质应用的溶剂成分，对于获得高质量的 MALDI-MSI 数据至关重要。然而，还没有同时优化这多个参数的既定方法。相反，优化是迭代执行的（即一次一个参数），这非常耗时并且可能导致整体非最佳设置。在本报告中，我们展示了使用新颖的实验设计和响应面方法来优化使用机器人喷雾器的 MALDI 基质应用的五个参数。测试了 32 种 MALDI 基质喷涂条件组合，这使我们能够阐明由 MALDI-MS（具体来说，使用 15 T 傅里叶变换离子回旋共振质谱仪）确定的每个应用参数之间的关系。因此，我们能够确定最佳的自动喷涂参数，最大限度地减少信号离域并实现高 MALDI 灵敏度。我们设想这种优化策略可用于其他基质应用方法以及其他分子类别和组织类型的 MALDI-MSI 分析。