Procedure 48 Separation and amperometric detection of hydrogen peroxide and l-ascorbic acid using capillary electrophoresis microchips

Abstract

Publisher Summary This chapter presents a procedure to design, integration, and alignment of an amperometric detector based on a metal-wire working electrode in a capillary electrophoresis (CE) microchip and determination of different parameters for the separation of L-ascorbic acid and hydrogen peroxide using Poly(methyl methacrylate (PMMA) and Topas CE-microchips. The amperometric detector is situated in the waste reservoir (B) with a three-electrode configuration. The reference and counter electrodes are coupled in a 250 mL micropipette tip. Separation and injection in the microchip is driven electrokinetically using high voltages. The different steps are: pretreatment, baseline stabilization, unpinched injection, and separation and detection. The chapter concludes that an appropriate integration and accurate alignment of the Pt wire working electrode is very important and it has to ensure the electrical isolation from the high separation voltage. The amperometric end-channel detectors allow an easy alignment of the electrode and a good isolation of the high voltage. The microchip material and pretreatment, which can affect to the state of the channels surface and electroosmotic flow (EOF), is also very important to obtain a good performance of the microchips.