Multistrand carbon fibers electrode for electrochemical detection in PDMS/Glass hybrid electrophoresis microchips

EUSTAQUIO M. ERRO; PATRICIA I. ORTIZ

Buenos Aires

Congreso; LACE 20212, 18 Simposio Latinoamericano en Aplicaciones de la Electroforesis Capilar y Tecnología del Microchip en Biotecnología, Biomedicina, Biofarmacia e Industria; 2012

Simposio Latinoamericano en Aplicaciones de la Electroforesis Capilar y Tecnología del Microchip en Biotecnología, Biomedicina, Biofarmacia e Industria

A multistrand carbon fibers electrode detector integrated with a polydimethylsiloxane/glass hybrid microchip is used for in-channel amperometric detection of Paracetamol, 4-aminophenol, Dopamine and Dopac after electrophoretic separation. Multistrand carbon fibers electrode was introduced into the microchip channel to increase the electroactive exposed area and amperometric signal, triple pulsed amperometric detection was performed. Two different mixtures, such as Paracetamol (PA) and 4-aminophenol (4AP) and Dopamine (DO) and Dopac were used to demonstrate electrode and microchip performance. The effect of injection and separation potentials, buffer pH and composition, surfactants addition and injection time were analyzed. Hydrodynamic voltammograms were used to select working potential values, and +0.9 V for PA and 4AP; and +0.8 V for DO and Dopac were chosen. The migration potential was modified in the 1500 to 2500 V range and values of 2000 V were mainly used. PA was the test analyte, calibration curves and stability experiments were performed with this compound and a limit of detection (LOD) of 6.3 μM was obtained. While current variation coefficients lower than 5% were observed, indicating that the electrophoretic separation is very reproducible.