Transmission Raman Spectroscopy (TRS)


Transmission Raman Spectroscopy is a method for analysing bulk turbidly scattering materials such as powders, tablets, suspensions and other chemical mixtures. It is ideally suited to rapid pharmaceutical analysis of tablets, capsules and powders and is the technology used in Cobalt’s TRS100 Rapid Analysis machine. The benefits in rapid analysis include:

  • Bulk-averaged assay of objects, i.e., the whole of the capsule or tablet is measured – no sub-sampling
  • Rejects surface signals from capsules, coatings and overlayers
  • Penetrates through up to 10mm or more of powders and tablets
  • Seconds per sample
  • Accuracy to ca. 1% relative error
  • No Sample preparation
  • Our technology is also able to directly measure polymorph content for concentration quantification and screening of polymorph forms

More information is available in our Technical and Application Notes Section.

Summary

TRS is an example of Raman spectroscopy where the light is collected from the opposite side of the sample to where it is illuminated. An advantage of TRS is that it samples the entire volume; this gives an average of the whole object and so removes sub-sampling effects of conventional Raman spectroscopy, eliminating bias to near surface samples areas. TRS also allows high quality chemical assay of the contents whilst suppressing the Raman and fluorescence signals originating from capsule shell.

Well-known techniques of chemometric analysis convert the spectra into accurate measures of concentration. All of the components are measured at the same time in the same measurement. Cobalt's software contains in-built routines for simplifying set-up of measurements with fully-customisable chemometric analysis software.

Transmission Raman can be applied throughout the pharmaceutical production chain on all types of material through up to ca. 10 mm of powder/solid; penetration increases in liquids/suspensions. The advantage is real-time, non-invasive and non-destructive quantitative analysis of a wide variety of materials.

Transmission Raman is not limited to pharmaceutical ingredients; most chemicals and chemical mixtures used in other industries (e.g. chemical and petrochemical) can be analysed in this way as well as biological tissue too.