Fast Analysis of Phenolic Acids by Microchip Capillary Electrophoresis with Serpentine Channel and End Wrapped Electrode

A microchip capillary electrophoresis with amperometric detection, mu CE-EC, for the analysis of phenolic acids is described The problem of noise-laden signal under high electric field was tackled by adopting the end-channel design of electrode configuration more specifically with the end-wrapped electrode configuration. At full stretch of effort, a finely tuned electrode could bring the detection limit well below micro molars for dopamine. At the end of the 10-cm serpentine micro-channel, a Pt electrode biased at +0.9 V (vs. Ag/AgCl) served as the working electrode Injection of gentisic acid, protocatechuic acid, vanillic acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid and chlorogenic acid gave repeatable results the migration time deviating within 3 80% (n = 7) and peak current between 1.45 and 4.50% Under the optimized conditions, the detection limits for phenolic acids could be brought down to the range between 1 82 mu M and 19 85 mu M at S/N = 3. The regression coefficient of the calibration curve over the range between 10 and 800 mu M was better than 0.995 The merits of increased efficiency with serpentine channel and improved sensitivity with end-wrapped electrode are promising. Beer samples were tested for feasibility as a routine tool.