title: A microfluidic chip for electrochemical conversions in drug metabolism studies.
abstract: We have designed a microfluidic microreactor chip for electrochemical conversion of analytes, containing a palladium reference electrode and platinum working and counter electrodes. The counter electrode is placed in a separate side-channel on chip to prevent unwanted side-products appearing in the measured spectrograms. Using this chip, cyclic voltammograms are measured in volumes of 9.6 nL. Furthermore the conversion efficiency of ferricyanide is characterized using UV/vis-spectroscopy. We have obtained an on-line conversion of 97% using a flow rate of 1 microL/min. We have used the microreactor chip to study the electrochemical metabolism pathway of amodiaquine using electrochemistry (EC)-liquid chromatography (LC)-mass spectrometry (MS). We have compared our results with measurements obtained with commercially available electrochemical flow-through cells. Using our chip it was possible to obtain similar results. Therefore, we have fabricated an electrochemical cell on-chip which is used successfully in EC-UV/vis and EC-LC-MS experiments.
authors.affiliation: BIOS - the Lab-on-a-Chip group, MESA+ Institute of Nanotechnology, University of Twente, 7500 AE, Enschede, The Netherlands. m.odijk@utwente.nl
authors.forename: M
authors.initials: M
authors.lastname: Odijk
authors.forename: A
authors.initials: A
authors.lastname: Baumann
authors.forename: W
authors.initials: W
authors.lastname: Lohmann
authors.forename: F T G
authors.initials: FT
authors.lastname: van den Brink
authors.forename: W
authors.initials: W
authors.lastname: Olthuis
authors.forename: U
authors.initials: U
authors.lastname: Karst
authors.forename: A
authors.initials: A
authors.lastname: van den Berg
mesh_terms: D000655:Amodiaquine / Q000378:metabolism; D002853:Chromatography, Liquid; D004353:Drug Evaluation, Preclinical; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D013058:Mass Spectrometry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004364:Pharmaceutical Preparations; D000655:Amodiaquine