Expanded Electrochemical Capabilities of the Electrospray Ion Source Using Porous Flow-Through Electrodes as the Upstream Ground and Emitter High-Voltage Contact

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• 作者：Gary J. Van Berkel and Vilmos Kertesz
• 刊名：Analytical Chemistry
• 出版年：2005
• 出版时间：December 15, 2005
• 年：2005
• 卷：77
• 期：24
• 页码：8041 - 8049
• 全文大小：248K
• 年卷期：v.77,no.24(December 15, 2005)
• ISSN：1520-6882

文摘

Use of a porous flow-through electrode at the upstreamground contact or at both the upstream ground contactand the high-voltage emitter contact in an electrospray ionsource was shown to provide for new types of electrochemical experiments utilizing only the electrochemistryinherent to electrospray. The normal stainless steel bore-through union serving as the upstream grounding pointin a floated electrospray emitter system was replaced witha high surface area porous flow-through electrode assembly to achieve effective electrochemical reduction ofanalytes at this point in positive ion mode, and effectiveelectrochemical oxidation of analytes in negative ionmode. This was demonstrated by the oxidation of 3,4-dihydroxybenzoic acid and reserpine in negative ion modeand by the reduction of thionine in positive ion mode. Inthe case of reversible oxidation (3,4-dihydroxybenzoicacid) and reduction (thionine) processes, partial rereduction and reoxidation of the products due to reaction withproducts generated by cathodic and anodic processes atthe emitter were observed, respectively. By implementingtwo high surface area porous flow-through electrodes inthe system, one as the upstream grounding point and theother as the emitter electrode, a multiple-step reactionscheme was achieved that included consecutive electrochemical reduction and oxidation reactions and a following chemical reaction as demonstrated by the hydroquinone tagging of an initially disulfide-linked peptide.