The Transmission Raman accessory is available for most of the HORIBA range of Raman microscope systems. It enables Transmission Raman spectroscopy to be undertaken in a simple and efficient format - all upon the standard Raman microscope. It provides a cost effective access to a technique ideally suited to bulk chemical analysis of opaque samples, including powders and tablets.

True bulk analysis via transmission Raman

Transmission Raman is based on the collection of Raman light propagating through the sample in the direction of the excitation laser – in essence, the sample is illuminated with the excitation laser from one side, and the Raman signal is collected from the other. Unlike its more traditional back-scattering counterpart which is vastly predominant in most dispersive Raman systems, the transmission configuration allows analysis of the full volume through which the light travels, even for opaque samples.

The Transmission Raman Accessory provides fast, reliable information about:

• API concentration
• Polymorphs analysis
• Crystallinity
• Powder composition and purity
• Content uniformity
• Solid form

Easy measurements with no sample preparation

As in classical Raman spectroscopy, transmission Raman is non-contact, non-invasive and non-destructive. It requires no sample preparation. Importantly, the measurement is insensitive to particle-size effects, sample homogeneity and orientation.

Top: Transmission Raman spectra from four tablets with varying API dosage (where percentages indicate variation relative to the standard production dosage).
Bottom: plot of API peak intensity versus concentration, showing excellent linearity.