Column Liquid Chromatography:  Equipment and Instrumentation

A review of pulsed electrochemical detection following liquid chromatography and capillary electrophoresis

“…Hence, in order to maintain a reactive electrode surface for reproducible detection, the waveform applied to a noble metal electrode must include a minimum of three steps: (1) detection step for electrocatalytic oxidation of the analyte of interest, (2) large positive, anodic potential for surface oxide formation step via oxidation, and (3) large negative, cathodic potential for surface oxide removal via reduction to restore electrode activity [10]. Neuburger and Johnson [11] determined that PAD at Au electrodes produced higher sensitivity and lower detection limits in comparison to Pt electrodes for the analysis of simple carbohydrates.…”

“…Pulsed voltammetry (PV) was introduced during the late 1980s as an optimization method for waveform parameters based on voltammetric response following the application of alternate anodic and cathodic polarizations. The technique cyclically executes a PED waveform to the electrode under hydrodynamic conditions, where incremental changes are made to the particular parameter optimized at each cycle of the waveform [10]. Current is sampled following t del , in order to minimize contributions from nonfaradaic currents, followed by anodic oxidation and cathodic reduction polarizations to maintain an active electrode surface.…”

“…As a result of its inherent sensitivity and compatibility with aqueous-based separation systems, applications of the technique have been realized in the toxicological, environmental, and pharmaceutical fields [71]. A generalization of the distribution of PED applications during the 1980s and 1990s is summarized in Table 1.…”

High‐Performance Liquid Chromatographic Analysis of Psychotropic and Endogenous Compounds

“…Evaporative light scattering detectors for nonchromophoric compounds are gaining in popularity and are used in analysis of various classes of lipids (LaCourse, 2002). The effluent from the column is nebulized with the aid of nitrogen or air, vaporizing the mobile phase and analyte molecules that pass through a laser beam.…”

“…A limitation of this type of detector is caused by the low transparency of many useful solvents (Skoog et al, 1998). Recent changes to interface systems that use spraying to induce rapid evaporation of the solvent provide good sensitivity and enhanced spectral quality (LaCourse, 2000).…”