Liquid chromatography /electrochemistry LCEC

Liquid chromatography/electrochemistry (LCEC) has become recognized as a powerful tool for the trace determination of easily oxidizable and reducible compounds. This is because detection of as little as 0.1 pmol of material is readily accomplished with relatively simple and inexpensive equipment. Initial interest in LCEC was generated by the determination of several aromatic matabolites of tyrosine in the central nervous system. However, the application of LCEC into other areas of biochemistry has begun at a growing pace. A bibliography of LCEC applications is available... 

A dual-electrode liquid chromatography-electrochemistry (LCEC) system used in the detection and identification of flavanols and procyanidins in wines and grape seeds is a valuable tool (30). Voltammetric behavior of phenolic compounds by LCEC could provide information that cannot be obtained using HPLC with UV detection, for which the identification is usually based on a comparison of the retention time with that of standard compounds, especially for the identification of catechins and procyanidins with a small amount of sample available (30). Figure 10 shows the procyanidins commonly found in wines. 

Whatever the future of electroanalysis really will be, it is worth considering what Faulkner recently said190 at a meeting on "Electrochemistry Faces Reality , where he mentioned more explicitly the significant impact of LCEC, liquid chromatography electrochemistry (see p. 346) and cybernetic instrumentation. 

Fig. 8. Correlation between digoxin concentration in patients by RIA and competitive heterogeneous enzyme immunoassay liquid chromatography/ electrochemistry (EIA-LCEC). A perfect correlation is represented by the solid line. (Reprinted with permission from Wehmeyer et al., 1986. Copyright 1986, American Chemical Society.)...

Because of this lack of resolving power, much electroanalytical research is aimed at providing increased selectivity. This can be accomplished in two ways. First, electrochemistry can be combined with another technique which provides the selectivity. Examples of this approach are liquid chromatography with electrochemical detection (LCEC) and electrochemical enzyme immunoassay (EEIA). The other approach is to modify the electrochemical reaction at the electrode to enhance selectivity. This... 

Kissinger P. LCEC The combination of liquid chromatography and electrochemistry. J Chem Ed 1983 60 308-11. 

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