On-valve electrochemical detector for high-speed flow injection analysis.
On-valve electrochemical detector for high-speed flow injection analysis.
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DOI：
10.1021/ac00220a032
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发表时间：
1990-11
影响因子：
7.4
通讯作者：
J. Wang;R. Li
中科院分区：
文献类型：
--
作者：
J. Wang;R. Li
Flow injection analysis (FIA) has proved highly useful in practical applications in fields as varied as clinical or agri-cultural analysis, process analytical chemistry, and environmental control (1-3). The method offers distinct advantages in flexibility, reproducibility, and sample throughput over conventional methods. Because of their inherent sensitivity and selectivity toward electroactive species, amperometric detectors have been proved to be extremely useful for FIA operation. A variety of electrochemical flow cells havebeen employed in connection with FIA, with the thin-layer and wall-jet designs representing the most popular ones. Other devices, based on porous, micro-, or mercury-drop electrodes, have also been employed. Despite their low dead volumes, traditional amperometric detectors are too bulky to address recent trends toward miniaturization of FIA systems (2, 4). This note describes a novel on-valve amperometric detector for FIA. Such a detector couples recent advances in areas of modified and microelectrodes (5) to achieve the desired se-lectivity and miniaturization. Rational tailoring of electrode surfaces permits extrapolation of well-defined solution chemistries to electrode surfaces, andhence to minimize/eliminate sample manipulation steps, commony performed in the FIA manifold channels. By coupling theselectivity advantage of modified surfaces with the miniaturization feature of ultramicroelectrodes, it is thus possible to integrate the detector into the injection valve. The small size of ultramicroelectrodes has been exploited by Jorgenson (6, 7) and Ewing (8) for on-column amperometric detection for open-tubular liquid chromatographyand capillary zone electro-phoresis, respectively. As applied to FIA operation, the present on-valve detector offers an exceptionally high sample
