title: In situ solution-phase Raman spectroscopy under forced convection.
abstract: In situ Raman spectra of solution-phase electrogenerated species have been recorded in a channel-type electrochemical cell incorporating a flat optically transparent window placed parallel to the channel plane that contains the embedded working electrode. A microscope objective with its main axis (Z) aligned normal to the direction of flow was used to focus the excitation laser beam (lambda exc = 532 nm) in the solution and also to collect the Raman scattered light from species present therein. Judicious adjustment of the cell position along Z allowed the depth of focus to overlap the diffusion boundary layer to achieve maximum detection sensitivity. Measurements were performed using a Au working electrode in iron hexacyanoferrate(II), [Fe(CN)6]4-, and nitrite, NO2-, containing aqueous solutions as a function of the applied potential, E. Linear correlations were found between both the gain and the loss of the integrated Raman intensity, IR, of bands, attributed to [Fe(CN)6]3- and [Fe(CN)6]4-, respectively, recorded downstream from the edge of the working electrode, and the current measured at the Au electrode as a function of E. The same overall trend was found for the gain in the IR of the NO3- band in the nitrite solution. Also included in this work is a ray trace analysis of the optical system.
authors.affiliation: Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, USA.
authors.forename: Huanfeng
authors.initials: H
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Qingfang
authors.initials: Q
authors.lastname: Shi
authors.forename: Zhenghao
authors.initials: Z
authors.lastname: Wang
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Scherson