High-resolution spatially resolved visible absorption spectrometry of the electrochemical diffusion layer

Abstract

M through 1 X lo4 M. The slope of the calibration curve was 0.506 f 0.035 pA/pM. The minimum detectable difference between the background and sample solution estimated by paired measurements (5) was 0.025 pM, which is over an order of magnitude lower than in the dc polarographic method (1 7).A voltammogram of a 5.0 X lo4 M Ti(IV) solution is presented in Figure 10. ACKNOWLEDGMENTThe authors thank Janet Osteryoung for helpful discussion.(1) Brdicka, R.; Wlesner, K.Concentration vs. distance profiles are fundamental to a variety of electrochemical processes but have not been observed previously at resolutions better than 25 pm. I n the present work, a collimated He-Ne laser beam was passed parallel to a planar electrode surface and then magntfied and imaged onto an array detector. Each pixel of the detector

Measurement of concentration profiles inside a nitrite ion-selective electrode membrane

“…The apparatus is similar to those described by Fukanaka et al (19) and later by McCreery and co-workers (20,21) for imaging the electrochemical diffusion layer at a solid electrode. Those authors have reported the spatial resolution due to diffraction from the lenses and refractive index effects is limited to 2 pm (19, 21), and due to edge diffraction effects a resolution of less than 5 pm is estimated near the electrode edge (21). We have recently reported the details of the design of the instrument and the electrochemical cells used to probe the distribution and diffusion rate of HzO inside a PVC-based membrane, using water-sensitive (solvatochromic) dyes (22).…”

Spectroelectrochemistry: In s itu UV ‐visible Spectroscopy

“…Using electrode potential modulation, it was possible to detect species down to 2 × 10 −8 M [173]. The technique was shown to work with a continuum source [174].…”

Visualization of Electrochemical Reactions by Redox-dependent Quenching of Photoluminescence from ZnS-AgInS2 Solid Solution Semiconductor Nanoparticles

“…Herein, we demonstrate a new means to visualize electrochemical reactions by the fluorescence quenching of the ZnS-AgInS 2 solid solution (ZAIS) NPs caused by electron transfer as a probe. In situ techniques to observe an electrochemical diffusion layer had been reported using a specially modified microscopy with diode array detector, [18][19][20] a confocal Raman microscopy, [21][22][23][24] and recently by a scanning electron microscopy with an x-ray spectrometer. 25 The present method detecting the variation in polarity can, in principle, cover many types of redox reactions if semiconductor NPs with an appropriate energy level and polarity are selected.…”