Electrochemical Detection of Selected Organic Components in the Eluate from High-Performance Liquid-Chromatography

Abstract

High-performance liquid chromatography can be combined with hydrodynamic thin-layer electrochemistry for determination of trace amounts of organic constituents in complex samples. With small and inexpensive analyzers based on these two techniques, as little as 1 pg of an electrochemically active component can be detected in a few minutes. Because many of the important low-molecular-weight organic constituents of body fluids— both endogenous metabolites and drugs—undergo electrochemical reactions, it seems reasonable to presume that useful assays might be developed by using the above methodology. Beginning to explore this presumption, we illustrate how uric acid, ascorbic acid, catecholamines, and related tyrosine metabolites might be measured in urine and serum. In some cases, liquid chromatography with electrochemical detection provides better sensitivity, selectivity, and speed than traditional methods, while minimizing the need for analytical reagents. We describe the basic approach and progress to date and suggest future applications.

S2k-Leitlinie Neuroendokrine Tumore

“…Die Neuronen-spezifische Enolase (NSE) ist ein zytoplasmatisches Enzym, welches in Zellen neuronalen und neuroektodermalen Ursprungs gefunden wird. Erhöhte Konzentrationen von NSE im Serum werden bei etwa 20 -45 % der differenzierten NET gefunden und scheinen mit einer negativen Prognose assoziiert zu sein [23,31,33,49,50,75]. Dabei weist die NSE im Vergleich zu Chromogranin A eine geringere Sensitivität und Spezifität für den Nachweis eines differenzierten NET auf und wird daher bei NET nicht als Routineparameter empfohlen [23,31,89].…”

Bioavailability studies of oral dosage forms containing levodopa and carbidopa using column-switching chromatography followed by electrochemical detection

“…To study the bioavailability and biopharmaceutical properties of these formulations, it became necessary to develop reliable methods for the simultaneous determination of these drugs and their metabolites. One of the most significant advances in quantitation techniques has been the development of electro-chemical detectors combined with high-performance liquid chromatography (HPLC-EC) which can offer the capability of selective and sensitive determination of electro-active oxidizable or reducible drug products, with little interference from biological matrix interferences 12,13 and with low limits of detection down to picogram quantities. 14 Pre-column switching has recently become a widespread means of improving the sample throughput, separation efficiency and, if the precolumn is used for concentration purposes, also the loadability of liquid chromatographic systems.…”

Measuring secretion in chromaffin cells using electrophysiological and electrochemical methods

“…Single‐cell amperometry is the simple miniaturization of electrochemistry (Kissinger et al. 1974) commonly implemented using carbon fibre microelectrodes (Ponchon et al. 1979) placed onto a cell to act as sensor.…”