Glossary · Automation fundamentals, platforms and components
Raman spectroscopy (PAT)
Also known as: Raman spectroscopy
German: Raman-Spektroskopie (PAT)
In process analytics, Raman spectroscopy is a vibrational spectroscopy method that measures the inelastic scattering of monochromatic laser light to identify and quantify substances. As a process analytical technology (PAT) tool, it measures composition in-line or at-line through probes, often without sampling.
- Automation components
- Process industry
In one sentence
Raman spectroscopy analyzes laser light scattering to identify and quantify substances in-line, a common tool in process analytical technology.
Example
A Raman probe in a bioreactor tracks glucose and lactate concentrations continuously, replacing manual samples every few hours.
How it applies
- Engineering: Raman analyzers use a laser, a fiber-coupled probe and a spectrometer. Quantitative results come from chemometric models that translate spectra into concentrations. Water gives a weak Raman signal, which makes the method useful in aqueous processes.
- Validation: The analyzer and its model must be qualified and maintained. Model updates are changes and follow change control in GMP environments.
- Documentation: Include the laser safety information (class, warnings, interlocks) in the operating manual, and describe how model versions, Calibration and probe cleaning are handled.
Raman vs. NIR spectroscopy
Both are vibrational methods used for PAT. NIR measures absorption and is strongly affected by water; Raman measures scattering and is less affected by water but can be disturbed by fluorescence. The choice depends on the substances and matrix.