Raman spectroscopy is used less commonly than other spectroscopic techniques by isotopic chemists. The University of Surrey has recently become a regional centre for the technique following our acquisition of a powerful high-resolution multi-laser Raman spectromicroscope (Renishaw inVia, model RE04, via EPSRC grant EP/M022749/1). This poster reports some early experience with the technique as applied to the analysis of deuterated compounds.

The spectrometer is based around Raman scattering from any of five lasers ranging from the ultraviolet to blue, green, red and near infrared (244–785 nm). The sampling beam has an area of just 2-10µm and hence the spectrometer has the ability to automatically scan tiny sample areas, offering the possibility of obtaining Raman imaging for 2-D and (via confocality) even 3-D samples. Investigations into isotopic applications of these multidimensional abilities are in progress.

The high resolution of the system also enables excellent spectra to be recorded from very tiny samples, e.g. from a small part of this 200µm crystal of [²H₈]naphthalene.

The poster provides examples of the following advantages when deuterated compounds are analysed by Raman:

1. Improved sensitivity is available via powerful lasers and digital spectral accumulation
2. Rapid generation of high quality one-dimensional Raman spectra from various sample types
3. Low matrix effects for glass enables direct analysis within ordinary sealed glass lab vials
4. High spectral and spacial resolution provides the ability to work with tiny samples/areas
5. Highly specific results, as vibrational modes can be very sensitive to isotopic substitution
6. Direct quantitative analysis of isotopic mixtures is possible by selecting the appropriate peaks
7. Low background from silicagel means TLC & HPTLC applications are possible
8. Surface enhanced Raman spectra (SERS) can be simply obtained via stable silver colloids