In addition, this research has also identified several highly beneficial analytical properties of this approach, including the ability to probe bulk content of powders and tissue in the absence of subsampling and to reject Raman and fluorescence components originating from the surface of the sample.
This desirable property removes a problem with conventional, widely used back-scattering Raman spectroscopy where the signal tends to be representative of the surface and near-surface composition.
[7][8] Pharmaceutical tablets and capsules are typically composed of a combination of APIs and excipients, each of which will produce a Raman spectral component with a relative intensity proportional to the ingredient concentrations.
Analysing Raman spectra to produce assay results requires a method to separate the individual spectral components and correlate their intensity contributions with a relative concentration measure.
Transmission Raman spectroscopy can be used as a process analytical technology (PAT) tool for the detection of physical state of the API and for obtaining qualitative and quantitative information about the composition.