Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a key tool for the analysis of biological tissues. It provides spatial and quantitative information about different types of analytes within tissue sections. Despite the increasing improvements of this technique, the low detection sensitivity of some compounds remains an important challenge to overcome. Poor sensitivity is related to weak ionization efficiency, low abundance of analytes and matrix ions, or endogenous interferences. On-tissue chemical derivatization (OTCD) has proven to be an important solution to these issues and is increasingly employed in MALDI MSI studies. OTCD reagents, synthesized or commercially available, have been essentially used for the detection of small exogenous or endogenous molecules within tissues. Optimally, an OTCD reaction is performed in mild conditions, in an acceptable range of time, preserves the integrity of the tissues, and prevents the delocalization. In addition to their reactivity with a targeted chemical function, some OTCD reagents can also be used as a matrix, which simplifies the sample preparation procedure. In this review, we present an exhaustive overview of OTCD reagents and methods used in MALDI MSI studies.

中文翻译：

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用于基质辅助激光解吸/电离质谱成像的组织化学衍生化试剂

基质辅助激光解吸/电离质谱成像 (MALDI MSI) 是分析生物组织的关键工具。它提供有关组织切片内不同类型分析物的空间和定量信息。尽管这项技术不断改进，但某些化合物的低检测灵敏度仍然是一个需要克服的重要挑战。灵敏度差与电离效率低、分析物和基质离子丰度低或内源性干扰有关。组织化学衍生化 (OTCD) 已被证明是解决这些问题的重要方法，并且越来越多地用于 MALDI MSI 研究。OTCD 试剂，合成的或市售的，主要用于检测组织内的外源性或内源性小分子。最理想的是，OTCD 反应在温和的条件下，在可接受的时间范围内进行，保持组织的完整性，并防止离域。除了与目标化学功能的反应性外，一些 OTCD 试剂还可以用作基质，从而简化样品制备程序。在这篇综述中，我们对 MALDI MSI 研究中使用的 OTCD 试剂和方法进行了详尽的概述。