Track-etched membrane-based dual-electrode coulometric detector for microbore/capillary high-performance liquid chromatography.

Track-etched membrane-based dual-electrode coulometric detector for microbore/capillary high-performance liquid chromatography.
Anal Chim Acta. 2020 Mar 15;1102:46-52
Authors: Mizuguchi H, Nishimori D, Kuwabara T, Takeuchi M, Iiyama M, Takayanagi T
Abstract
The electrochemical flow cell containing track-etched microporous membrane electrodes was applied to a dual-electrode coulometric detector for microbore/capillary HPLC with a small injection volume and low eluent flow rate. The proposed flow cell with a 0.1-mm diameter inlet channel gave a detection volume of 0.08 nL per electrode, which was determined by the eluent flow through the electrode. For the dual-electrode detector, the calculated volume was 0.24 nL. The efficiency of electrooxidation of l-ascorbic acid increased as the flow rate decreased and was close to 100% when the flow rate was below 50 μL min-1, which is a common flow rate in microbore or capillary liquid chromatography. Catecholamines, such as noradrenaline, adrenaline, and dopamine, were detected by total conversion with two-electron oxidation in the potential range from 0.8 to 1.0 V vs. Ag/AgCl after separation with a microbore column. These peaks were accompanied by corresponding cathodic peaks derived from quasi-stable electrooxidation products of the catecholamines. The detection limits of noradrenaline, adrenaline, and dopamine were 0.1, 0.1, and 0.2 μM, respectively. The RSD values for five replica...

Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Mizuguchi H, Nishimori D, Kuwabara T, Takeuchi M, Iiyama M, Takayanagi T Tags: Anal Chim Acta Source Type: research