Development of inlaid electrodes for whole column electrochemical detection in HPLC

An electrochemical microfluidic device has been fabricated on PET (polyethylene terephthalate) substrate using an imprinting method. The imprinting transfers patterns from a stamp into a substrate mechanically. However, a blanket mould imprinting process has been introduced to embed the photolithographically produced gold metal electrode lines into the PET substrate resulting in an individually addressable array flush to better than 100 nm. The device formed one wall of a packed chromatography column. The array was electrochemically characterised using standard redox probes in both stagnant conditions and under flow. Both numerical modelling and experimental data show improved sensitivity under flow and a limiting current which scaled linearly with the cube root of the volume flow rate. A chromatographic separation of the bioanalytical significant neurotransmitter dopamine (DA) and its metabolite DOPAC was achieved and electrochemically detected at multiple locations within the column. The PET device was stable and robust to leaks to pressures well in excess of those required for chromatographic separations.This work was financially supported by the Center for Integrated Human Sensing System at Hanyang University. The authors would like to acknowledge Dr James Covington and Mr Fauzan Che Harun from the Sensors Research Laboratory of University of Warwick for assisting in the 3D model fabrication. PL Leow acknowledges Universiti Teknologi Malaysia for the financial support for her research studies. BA Patel acknowledges support provided by an EPSRC LSI Postdoctoral Fellowship Grant