Flow injection analysis conventional electrodes

More unusual ideas involve the flow of solution through tubular electrodes or the use of so called wall jet electrodes in which a rapid jet of solution is impinged directly onto a small electrode. Since these methods involve flow of solution through tubing rather than an open cell, they introduce the possibility of automated analysis. The samples could be automatically injected into a continuous flow of fresh supporting electrolyte - flow injection analysis. Conventional polarography does not lend itself as easily to automation as does this version of stripping voltammetry. 

The combination of ASV with the flow injection analysis (FIA) improves the reproducibility and versatility of the anodic stripping procedure. For a conventional operation the detection limit is of 10" M. The disadvantage of the FIA, namely the short deposition time, can be compensated by repeated reversals of the flow direction [174]. The multiple passage of the same sample along the mercury-plated carbon fiber electrode increases the effective deposition time and thus the stripping current response. 

Five types of amperometric detection have been applied for enzyme-based ECIA. They are flow-injection analysis with electrochemical detection (FIAEC), liquid chromatography with electrochemical detection (LCEC), amperometric detection with interdigitated array electrodes (IDA), rotating disk electrode (RDE) amper-ometry, and scanning electrochemical microscopy (SECM). Of these, the two conventional types, FIAEC and LCEC, shall be discussed in this section, leaving the discussion of the other types to Section V on miniaturized immunoassays. 

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