Two-step matrix application technique to improve ionization efficiency for matrix-assisted laser desorption/ionization in imaging mass spectrometry
Two-step matrix application technique to improve ionization efficiency for matrix-assisted laser desorption/ionization in imaging mass spectrometry
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DOI：
10.1021/ac060974v
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发表时间：
2006-12-15
影响因子：
7.4
通讯作者：
Setou, Mitsutoshi
中科院分区：
文献类型：
--
作者：
Sugiura, Yuki;Shimma, Shuichi;Setou, Mitsutoshi
提出了一种用于直接组织质谱分析的新型矩阵应用方案。基质辅助激光解吸/电离是一种流行的直接组织分析和成像质谱的电离程序。通常，通过移液管或自动分配机分配液滴或通过空气刷来施加基质。这些技术非常简单，但是很难在组织表面获得均匀的基质晶体，并且不均匀的晶体降低了光谱质量。在这里，我们报告了一个新的矩阵应用程序协议，这是一个喷雾和分配液滴的组合，我们已经成功地克服了这些问题，在传统的矩阵应用在组织表面。我们把我们的新技术称为“喷雾-液滴法”。在这种技术中，通过喷射形成的微小基质晶体作为晶体生长的种子。我们的技术导致矩阵点，均匀填充微小晶体。这样的基质晶体显著地改善峰强度和信噪比。在大鼠脑切片上的一个实例中，可检测峰的数量增加，并且在我们的方法中m/z 5440的信号强度近似于常规方法的30.6倍。我们使用这种喷雾液滴的方法与化学喷墨技术的矩阵沉积成功的MALDI成像的信号，这是无法检测到从传统的矩阵应用。
A novel matrix application protocol for direct tissue mass spectrometry is presented. Matrix-assisted laser desorption/ ionization is a popular ionization procedure for direct tissue analysis and imaging mass spectrometry. Usually, matrixes are applied by dispensing droplets through either pipettes or automated dispensing machines, or by air-brushing. These techniques are very simple, but it was difficult to obtain uniform matrix crystals on the tissue surface, and nonuniform crystals degrade the spectrum qualities. Here we report a new matrix application protocol, which is a combination of spraying and dispensing droplets, and we have succeeded in overcoming these problems in conventional matrix applications on tissue surfaces. We call our new technique the "spray-droplet method". In this technique, tiny matrix crystals formed by spraying act as seeds for crystal growth. Our technique leads to matrix spots that are filled homogeneously with minute crystals. Such matrix crystals dramatically improve peak intensity and signal-to-noise ratio. In an example on a rat brain section, the number of detectable peaks was increased and signal intensity of m/z 5440 in our method was similar to 30.6 times higher than that in conventional methods. We used this spray-droplet method with a chemical ink-jet technology for matrix deposition to succeed in MALDI imaging of signals, which were undetectable from the conventional matrix applications.