Liquid chromatography/electrochemistry

Pulsed amperometric detection (PAD), introduced by Johnson and LaCourse (64, 65) has greatly enhanced the scope of liquid chromatography/electrochemistry (66). This detection mode overcomes the problem of loss of activity of noble metal electrodes associated with the fixed-potential detection of compounds such as carbohydrates, alcohols, amino acids, or aldehydes. Pulsed amperometric detection couples tlie process of anodic detection with anodic cleaning and cathodic reactivation of a noble metal electrode, thus assuring a continuously cleaned and active... 

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... 

Shoup, R. E. Recent Reports on Liquid Chromatography/Electrochemistry, West Lafayette BAS Press 1982... 

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. 

A variety of analytical techniques are used to measure PCP, including gas chromatography-mass spectrometry (GC-MS), which has a detection limit of 7.6 pg/kg honey (Muino and Taiza.no 1991), liquid chromatography with fluorescence detection (de Ruiter et al. 1990), and liquid chromatography-electrochemistry (LC-ED) procedures (Butler and Pont 1992). At present, GC-MS is the most accurate, but LC-ED is used most frequently (Butler and Pont 1992). 

Butler, E.C.V. and G.D. Pont. 1992. Liquid chromatography-electrochemistry procedure for the determination of chlorophenolic compounds in pulp mill effluents and receiving waters. Jour. Chromatogr. 609 113-123. 

LA Allison, GS Mayer, RE Shoup. o-Phthalaldehyde derivatives of amines for high-speed liquid chromatography/electrochemistry. Anal Chem 56 1089-1096, 1984. 

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. 

SM Lunte, KD Blankenship, SA Read. Detection and identification of procyanidins and flavanols in wine by dual-electrode liquid chromatography-electrochemistry. Analyst 113 99-102, 1988. 

Liquid chromatography/electrochemistry Low-energy electron diffraction Mercury flow rate (in polarography)... 

Kissinger, P.T. Radzik, D.M. Liquid chromatography/ electrochemistry in pharmaceutical analysis. Drugs Pharm. Sci. 1991, 47, 65-100. 

Roston, D.A. Kissinger, P.T. Series dual-electrode detector for liquid chromatography/electrochemistry. Anal. Chem. 1982, 54, 429 34. 

Radzik, D.M. Brodbelt, J.S. Kissinger, P.T. Determination of toxic azo dye metabolites in vitro by liquid chromatography/electrochemistry with a dual-electrode detector. Anal. Chem. 1984, 56, 2927-2931. 

Lunte, C.E. Kissinger, P.T. Study of the tautomerization of quinonoid dihydropterins by liquid chromatography/ electrochemistry. Anal. Chim. Acta 1984, 158, 33-41. 

Jacobs, W.A. Kissinger, P.T. Nitroaromatic reagents for determination of amines and amino acids by liquid chromatography/electrochemistry. J. Liq. Chromatogr. 

Allison, L.A. Myer, G.S. Shoup, R.E. The o-phthalaldehyde derivatives of amines for high-speed liquid chromatography/ electrochemistry. Anal. Chem. 1984, 56, 1089-1096. 

Fleming, L.H. Reynolds, J.N.C. Separation and detection of closely related endorphins by liquid chromatography-electrochemistry. J. Chromatogr. 1986, 375, 65-73. 

RE Shoup. Liquid chromatography/electrochemistry. In Cs. Horvath, ed. High Per-Copyright 2002 by Marcel Dekker. All Rights Reserved. 

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.)...

Meinsma, D.A. Radzik, D.M. Kissinger, P.T. Determination of common anedgesics in serum and urine by liquid chromatography/electrochemistry. J.Liq.Chromatogr., 1983, 6, 2311-2335 [serum urine electrochemical detection simultaneous codeine, methyl salicylate, naproxen, phenacetin, salicylic acid]... 

Shoup, R.E., Ed, "Recent Reports on Liquid Chromatography/ Electrochemistry" BAS Press West Lafayette, Indiana, 1982,... 

Khaledi MG, Dorsey JG (1985) Hydro-organic and micellar gradient elution liquid chromatography with electrochemical detection. Anal Chem 57 2190-2196 Kissinger PT (1989) Biomedical applications of liquid chromatography-electrochemistry. J Chromatogr 488 31-52... 

Shoup RE (1986) Liquid chromatography/electrochemistry. In High-performance liquid chromatography, vol 4. Academic Press, New York, pp 91-194 Smyth MR (1986) Determination of vincamine in plasma by high-performance liquid chromatography with voltammetric detection. Analyst 111 851-852 Stulik K, Pacakova V (1987) Electroanalytical measurements in flowing liquids. Ellis Horwood, Chichester... 

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