Comparative Analysis of Derivatization Reagents for Catecholamines and Amino Acids

We compared four derivatization reagents to analyze catecholamines and amino acids by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. 2,4,6-Trimethylpyrylium tetrafluoroborate (TMPy), 2,4-diphenyl-pyranylium tetrafluoroborate (DPP-TFB), 4-(anthracen-9-yl)-2-fluoro-1-methylpyridin-1-ium iodide (FMP-10), and triphenyl pyrilium (TPP) were used as derivatization reagents that can specifically modify primary amines or hydroxy groups in target molecules. Three derivatization reagents, not including TPP, reacted with all target molecules. The derived catecholamines dopamine and L-DOPA, and the amino acids GABA and glycine, were efficiently ionized in comparison with non-derivatized targets. Comparative analysis indicated that TMPy and FMP-10 produced general increases in signal-to-noise ratios (S/N), whereas DPP and TPP produced specific increases in the S/N of GABA and DA. Notably, TMPy is a small molecule that efficiently reacts with target molecules due to the absence of high bulk and steric hinderance.

我们比较了四种衍生化试剂，用于通过基质辅助激光解吸/电离（MALDI）质谱法分析儿茶酚胺和氨基酸。使用了四氟硼酸2,4,6 - 三甲基吡喃鎓（TMPy）、四氟硼酸2,4 - 二苯基吡喃鎓（DPP - TFB）、碘化4 -（蒽 - 9 - 基）- 2 - 氟 - 1 - 甲基吡啶 - 1 - 鎓（FMP - 10）和三苯基吡喃鎓（TPP）作为衍生化试剂，它们能够特异性修饰目标分子中的伯胺或羟基。三种衍生化试剂（不包括TPP）与所有目标分子发生反应。与未衍生化的目标相比，衍生化的儿茶酚胺多巴胺和L - 多巴以及氨基酸γ - 氨基丁酸（GABA）和甘氨酸能够高效电离。比较分析表明，TMPy和FMP - 10使信噪比（S/N）普遍提高，而DPP和TPP使GABA和多巴胺的信噪比有特异性提高。值得注意的是，TMPy是一种小分子，由于没有较大的体积和空间位阻，它能与目标分子高效反应。