以组氨酸钴吸氧初期和吸氧24h两个阶段的样品为研究体系,采用电喷雾多级串联质谱技术研究了组氨酸钴氧载体的质谱裂解过程.在其质谱裂解图谱中发现了氧合配合物的碎片峰,将该氧合配合物碎片峰进一步裂解,可得到失去中性氧分子的子离子碎片峰,从而用MS对其二聚体氧合形态和氧合物中O2的存在进行了确认;根据所得质谱数据对组氨酸钴氧合产物的结构、裂解方式及O2的存在形态进行了初步的推断.结果表明,组氨酸钴的吸氧过程是一个动态的变化过程,配合物在吸氧初期和吸氧24 h后,分子O2均以超氧形式存在,但经历了从双核超氧桥联配合物到双核双桥联超羟基配合物的转变,表明电喷雾质谱(ESI-MS)可作为研究氧合反应和表征氧合配合物的有效手段.%Histidine-cobalt complex is a known model compound of oxygen carriers. The investigation of its oxygenation is of great significance in revealing the reversible oxygenation mechanism of oxygen carriers. In this paper, a new method was proposed to directly investigate the oxygenation of histidine-cobalt complex by electrospray tandem mass spectrometry. The fragment ions of the oxygenated complexes were found from both ' aqueous samples of histidine-cobalt complex separately adsorbing oxygen at early time and continuously adsorbing oxygen for 24 h. The fragment ions of the oxygenated complexes were confirmed by its sub-fragment ion which just lost a neutral fragment of dioxygen by further fragmentation. Based on these results, the structure, mechanism and the species of dioxygen existed in the complex were deduced. The results show that the absorption process is a dynamic process, and the structure of the oxygenated complex changes from dinuclear superoxo-bridged complex to dinuclear superoxo-hydroxo dibridge complex according to the evolution of oxygenation. ESI-MS may be an effective technique to research the oxygenation and characterize oxygenated complexes.
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