鲁米诺电化学发光关键中间体的质谱在线表征  

On-line Mass Spectrometric Characterization of Key Intermediates in Luminol Electrochemiluminescence

作　　者：于凯 乔志媛 张铭旺 朱乾龙 刘吉林 王雪凝 余千云 姜延晓 张洪 姜杰 YU Kai;QIAO Zhi-yuan;ZHANG Ming-wang;ZHU Qian-long;LIU Ji-lin;WANG Xue-ning;YU Qian-yun;JIANG Yan-xiao;ZHANG Hong;JIANG Jie(Marine Science and Technology,Harbin Institute of Technology(Weihai),Weihai 264209,China;School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]哈尔滨工业大学(威海)海洋科学与技术学院,山东威海264209 [2]哈尔滨工业大学化学化工学院,黑龙江哈尔滨150001

出　　处：《质谱学报》2024年第1期141-148,I0005,共9页Journal of Chinese Mass Spectrometry Society

基　　金：国家自然科学基金(22074026)。

摘　　要：鲁米诺优异的电化学发光性能使其在分析检测领域获得了广泛应用,然而,与反应机理相关的直接数据鲜有报道。本研究基于电化学-微米管-质谱(electrochemistry-micro tube-mass spectrometry,EC-MT-MS)技术,选用具有微米尖端的高硼硅玻璃管作为电解池和质谱电喷雾离子源,通过内置2根铂金丝电极连接自制的电化学工作站,实现鲁米诺电化学发光反应的实时在线质谱分析,结合串联质谱技术确认了相关产物的分子结构。本工作发现了鲁米诺电化学反应的2种关键中间体以及发光产物3-氨基邻苯二甲酸,确认了过氧化氢对于鲁米诺发光反应的增益机制。此外,将1,4-苯醌加入鲁米诺-过氧化氢体系,验证了超氧根阴离子自由基(O^(·-)_(2),源于过氧化氢)在鲁米诺电发光反应过程中的核心作用,本实验结果为研究鲁米诺发光机理提供了直接的数据参考。Due to the low oxidation potential and high electrochemiluminescence(ECL)quantum yield,Luminol has been widely applied in analytical and detection fields,especially in immunoassay,food safety and environmental monitoring.However,there is a lack of sufficient experimental evidence on the ECL mechanism of Luminol,which affects the further improvement of its ECL efficiency.Herein,an electrochemistry-micro tube-mass spectrometry(EC-MT-MS)device was constructed for on-line monitoring of Luminol ECL reaction.In this EC-MT-MS device,a high borosilicate glass tube with a nano tip was used as electrochemical cell and electrospray ionization source,a platinum working electrode and a platinum counter electrode were inserted into the tube and connected to a customized power station,which could simultaneously input a low voltage(volt level)for the ECL reaction and a high voltage(kilovolt level)for the formation of electrospray.Prior to the EC-MT-MS experiment,the composition of the reaction solution was optimized to obtain the highest MS signal response,and Luminol was dissolved in acetonitrile-water(4∶1,V/V)solvent with ammonium acetate as the electrolyte.The concentrations of Luminol and ammonium acetate in the prepared solution were both 0.1 mmol/L,and the pH was adjusted to 11 using ammonium aqueous.The oxidation potential of Luminol was subsequently studied using a traditional three-electrode system by cyclic voltammetry in the same solution,and the determined oxidation potential for ECL reaction was 0.87 V.During the EC-MT-MS measurements,(2.5 kV+0.87 V)and 2.5 kV were input to the working and counter through the power station,respectively.A series of short-lived intermediates and products such as L 1(m/z 198)and the luminescent precursor AP-(m/z 180)in the Luminol ECL reaction process were successfully captured and analyzed by MS.The molecular structures of these products were characterized by tandem mass spectrometry(MS n)technique.There are mainly two fragments of m/z 163,136 present in the MS 2 spectrum of lumines

关 键 词：电化学-微米管-质谱(EC-MT-MS) 鲁米诺 过氧化氢 电化学发光 3-氨基邻苯二甲酸 

分 类 号：O657.63[理学—分析化学]