Linearly moving low-volume spectroelectrochemical cell for microliter-scale surface-enhanced resonance Raman spectroscopy of heme proteins

Surface-enhanced resonance Raman spectra of cytochrome c on silver electrodes coated with self-assembled monolayers of mercaptopropionic acid were recorded at different potentials using 50 μL of a micromolar solution. For this purpose, a linearly moving, low-volume, small spectroelectrochemical cell was designed and used together with a Raman microprobe. The quality of the spectra obtained is good, and the spectra show essentially the same features reported by other authors using much larger volumes. The cell described in this paper is shown to be useful for studying the spectroelectrochemistry of photosensitive compounds such as heme proteins, which are available only in very small amounts (nanomoles to picomoles).