Carbon-polymer chips as sensitive electrochemical detectors for micro-lqiuid chromatography

Recent developments in microcolumn liquid chromatography

An overview of the most recent developments in microcolumn liquid chromatography (LC) is presented. A short theoretical discussion on chromatographic dilution and extracolumn bandbroadening is given and also the recent progress and advances in column technology and instrumentation are reviewed. However, the emphasis of this review is on miniaturized sample clean-up, sample introduction techniques and on both established and more recent detection techniques for microcolumn LC. The hyphenation of miniaturized LC columns with other techniques, specifically on multidimensional chromatography and the coupling of microcolumn LC to mass spectrometry is discussed in detail. Both the on-line and automated off-line interfacing to other separation and detection techniques will also be addressed. Finally, a number of typical microcolumn LC applications are presented in order to demonstrate the potential of microcolumn LC methods in a variety of scientific areas.

Rapid-scan hydrodynamic voltammetry and cyclic voltammetry of pharmaceuticals in flow injection analysis conditions

An on-line rapid-scan electrochemical detector is described for HPLC and FIA systems. Its practical use in qualitative analysis is demonstrated for 19 drug substances. The detector can be operated to record convection/diffusion-controlled (S-shaped), or diffusion-controlled (peak-shaped) voltammograms. In the latter mode, on-line cyclic voltammetry measurements are possible. The cell can also be used as an amperometric detector for conventional, microbore and micro-LC methods. Detection limits are of the order of 10 pg (conventional and microbore HPLC), or at the sub-picogram level (micro-LC). For scanning work, drugs can be analysed at mg l-1 levels in an FIA setup.