Research of detection of low molecular weight compounds on human health and biological systems become increasingly important. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), a soft ionization equipment, is a rapid, reliable, high-sensitivity, high-throughput and simple test instrument. However, the application of MALDI-TOF MS in the analysis of small molecules (<500 Da) has become a great challenge because of the interference from the conventional matrices in low mass region when using conventional matrices. In this research, tricobalt tetraoxide (Co₃O₄) nanocrystals with rich surface hydroxyl groups were synthesized and served as novel matrices for the detection of small molecules by MALDI-TOF MS. In comparison with conventional organic matrices, the use of as-prepared Co₃O₄ nanocrystal matrices showed little matrix background interference, good reproducibility and high signal intensity in the analyses of amino acids, harmful additives and pesticide residues. For the detection of most amino acids, Co₃O₄ nanocrystal matrices have good detection performance both in the positive and negative ion modes and have a unique decarboxylation peak in the positive ion mode, which is conducive to the identification of amino acids. In addition, Co₃O₄ nanocrystals are completely feasible to test triadimefon, pirimicarb and other pesticide residues, as well as additives such as bisphenol A and melamine in the positive ion mode. It is also feasible to detect small molecule compounds in practical samples using Co₃O₄ nanocrystals as matrices. We believe the work provides an alternative approach for the detection of small molecules and expands the application scope of Co₃O₄ nanocrystals.

检测低分子量化合物对人体健康和生物系统的研究变得越来越重要。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）是一种软电离设备，是一种快速、可靠、高灵敏度、高通量和简单的测试仪器。然而，MALDI-TOF MS在小分子（<500 Da）分析中的应用已经成为一个巨大的挑战，因为在使用传统基质时，在低质量区域会受到传统基质的干扰。在这项研究中，四氧化三钴（Co ₃ O ₄) 合成了具有丰富表面羟基的纳米晶体，并作为 MALDI-TOF MS 检测小分子的新型基质。与传统有机基质相比，所制备的Co ₃ O ₄纳米晶基质在氨基酸、有害添加剂和农药残留分析中表现出基质背景干扰小、重现性好、信号强度高的特点。对于大多数氨基酸的检测，Co ₃ O ₄纳米晶基质在正离子模式和负离子模式下均具有良好的检测性能，并且在正离子模式下具有独特的脱羧峰，有利于氨基酸的鉴定。此外，Co ₃ O ₄纳米晶在正离子模式下检测三唑酮、抗蚜威等农药残留，以及双酚A、三聚氰胺等添加剂是完全可行的。_{使用Co 3} O ₄纳米晶体作为基质检测实际样品中的小分子化合物也是可行的。我们相信这项工作为小分子的检测提供了一种替代方法，并扩大了Co ₃ O ₄纳米晶体的应用范围。