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提出一种同轴式电化学电喷雾质谱离子源,用于电化学与质谱分析在线联用.离子源结构简单,造价低廉,容易制作.离子源内的电化学反应器工作在两电极模式,利用自制的悬浮在电喷雾高压上的无线电化学工作站控制.使用二苯基蒽或三乙胺的乙腈溶液作为分析物,全面测试了离子源的性能,包括电势控制精度、电化学转化率、响应时间和抗污能力等.测试溶液添加浓度约10mmo.lL-1的银盐作为电解质和去极剂,将溶液电阻降至250Ω,提高了在线联用的电势控制精度.所测二苯基蒽溶液流动时的伏安曲线与常规三电极体系的循环伏安曲线基本一致.在3.6μL.min-1的流速下,离子源的响应时间不超过5s,三乙胺的电化学转化率高达77%.利用此离子源,研究了蒽的电化学衍生反应,衍生试剂为十二胺.蒽作为一种非极性物质,不能为常规电喷雾质谱检测.而利用电化学电喷雾质谱离子源,蒽首先发生电化学氧化反应,进而与衍生试剂作用生成各种极性物质,被电喷雾质谱检测.依据质谱检测到的主要反应产物的相对分子质量与结构提出了衍生反应的机理,有助于理解蒽的复杂电化学行为.
A coaxial electrospray ionization mass spectrometer ion source is proposed for on-line electrochemical and mass spectrometry analysis.The ion source has the advantages of simple structure, low cost and easy fabrication.The electrochemical reactor in the ion source operates in a two-electrode mode and utilizes Self-contained radio-chemical workstation suspended on electrospray high voltage The performance of the ion source was thoroughly tested using either diphenylanthracene or triethylamine in acetonitrile as the analyte, including potential control accuracy, electrochemical conversion, response time And anti-fouling ability, etc. Test Solution The silver salt with the concentration of about 10mmo.lL-1 was added as electrolyte and depolarizer to reduce the solution resistance to 250Ω, which improved the potential control accuracy of the in-line combination.The measured diphenylanthracene solution The voltammetry curves of the three-electrode system were in good agreement with the cyclic voltammetry curves of the conventional three-electrode system.The response time of the ion source was less than 5s at a flow rate of 3.6μL · min-1, and the electrochemical conversion of triethylamine was as high as 77% Using this ion source, the electrochemical derivatization of anthracene was studied, and the derivatization reagent was dodecylamine.As a kind of nonpolar substance, anthracene could not be detected by conventional electrospray ionization mass spectrometry.But using electrospray ionization mass spectrometry ion source, Anthracene first electrochemical oxidation reaction, and then with the derivatization reagent to generate a variety of polar substances detected by electrospray ionization mass spectrometry detected by the main reaction products of the relative molecular mass and structure of the derivative reaction mechanism is conducive to Comprehend the complex electrochemical behavior of anthracene.