A simultaneous determination of (-) epictechin, (+) catechin, gentisic acid, ferulic acid, quercetin and gallic acid in red wine by capillary zone electrophoresis with electrochemical detection(CE ED) was reported. Th...A simultaneous determination of (-) epictechin, (+) catechin, gentisic acid, ferulic acid, quercetin and gallic acid in red wine by capillary zone electrophoresis with electrochemical detection(CE ED) was reported. The effects of potential of working electrode, pH and concentration of running buffer, separation voltage and injection time on CE ED were investigated. Under the optimum conditions, these six analytes could be separated in a 100 mmol/L borate buffer(pH=9 24) within 30 min. A 300 μm diameter carbon disk electrode has a good response at +0 85 V( vs . SCE) for all analytes. The responses were linear over two orders of magnitude with detection limit( S/N =3) ranged from 7×10 -8 g/mL to 1 4×10 -7 g/mL for all six analytes. This method has been used for the determination of these analytes in red wine without enrichment, and the assay result was satisfactory.展开更多
A poly(methyl methacrylate)-based capillary electrophoresis microchip, integrated with a microelectrode-based end-column amperometric detection, was described. A short unclosed portion of the separation channel from t...A poly(methyl methacrylate)-based capillary electrophoresis microchip, integrated with a microelectrode-based end-column amperometric detection, was described. A short unclosed portion of the separation channel from the detection cell was used as a working-electrode guide channel. With the aid of a three-dimension micropositioner and an optical microscope, a home-made 6 μm carbon-fiber microdisk electrode(tip diameter of 20 μm) was positioned along the guide channel at 30 μm distance from the channel outlet. With dopamine and catechol the as model analytes, the analytical performance of the system was demonstrated and the detection limit of 1.6×10 -7mol/L for dopamine was achieved, to our knowledge, which is the lowest value than that from published literatures using electrophoresis microchip with end-column amperometric detection.展开更多
文摘A simultaneous determination of (-) epictechin, (+) catechin, gentisic acid, ferulic acid, quercetin and gallic acid in red wine by capillary zone electrophoresis with electrochemical detection(CE ED) was reported. The effects of potential of working electrode, pH and concentration of running buffer, separation voltage and injection time on CE ED were investigated. Under the optimum conditions, these six analytes could be separated in a 100 mmol/L borate buffer(pH=9 24) within 30 min. A 300 μm diameter carbon disk electrode has a good response at +0 85 V( vs . SCE) for all analytes. The responses were linear over two orders of magnitude with detection limit( S/N =3) ranged from 7×10 -8 g/mL to 1 4×10 -7 g/mL for all six analytes. This method has been used for the determination of these analytes in red wine without enrichment, and the assay result was satisfactory.
文摘A poly(methyl methacrylate)-based capillary electrophoresis microchip, integrated with a microelectrode-based end-column amperometric detection, was described. A short unclosed portion of the separation channel from the detection cell was used as a working-electrode guide channel. With the aid of a three-dimension micropositioner and an optical microscope, a home-made 6 μm carbon-fiber microdisk electrode(tip diameter of 20 μm) was positioned along the guide channel at 30 μm distance from the channel outlet. With dopamine and catechol the as model analytes, the analytical performance of the system was demonstrated and the detection limit of 1.6×10 -7mol/L for dopamine was achieved, to our knowledge, which is the lowest value than that from published literatures using electrophoresis microchip with end-column amperometric detection.
