title: A microfluidic channel flow cell for electrochemical ESR.
abstract: The design, fabrication, and characterization of microfluidic channel flow devices for in situ simultaneous hydrodynamic electrochemical ESR is reported. The microelectrochemical reactors consist of gold film electrodes situated within rectangular ducts of height 350 microm and widths in the range 500-2000 microm. The small dimensions of the channels result in minimal dielectric loss when centralized within a cylindrical TE011 resonant cavity, leading to a high level of sensitivity. This is demonstrated by using the one-electron oxidation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in acetonitrile as a model system, wherein the ESR spectra obtained for the corresponding stable radical cation are of a high signal-to-noise ratio. Signal intensity is measured as a function of flow rate for this system, and the behavior is validated by means of 3-dimensional numerical modeling of the hydrodynamic flow profile.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Wain
authors.forename: Richard G
authors.initials: RG
authors.lastname: Compton
authors.forename: Rudolph
authors.initials: R
authors.lastname: Le Roux
authors.forename: Sinéad
authors.initials: S
authors.lastname: Matthews
authors.forename: Kamran
authors.initials: K
authors.lastname: Yunus
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Fisher