Glossary · Automation fundamentals, platforms and components
Near-infrared (NIR) spectroscopy
Also known as: NIR spectroscopy, NIRS
German: NIR-Spektroskopie
In process analytics, near-infrared (NIR) spectroscopy is a measurement method that analyzes how a sample absorbs near-infrared light to determine properties such as moisture, composition or concentration, often inline and without sample preparation.
- Automation components
- Process industry
In one sentence
NIR spectroscopy analyzes near-infrared light absorption to measure properties such as moisture or composition, often inline.
Example
An NIR probe in a blender measures the active ingredient concentration of a powder mix in real time, so blending can stop once the mix is uniform.
How it applies
- Engineering: NIR analyzers need chemometric calibration models built from reference samples. Probes are installed inline, online or at-line.
- Operation: Model performance must be monitored; changes in raw materials or process conditions can make the model invalid.
- Documentation: Document the calibration model, its version, validity range and maintenance. In regulated industries such as pharma, NIR methods used for release decisions need validation, and model changes fall under change control.
- Maintenance: Probe windows must be cleaned and the instrument checked with reference standards at defined intervals.
NIR spectroscopy vs. laboratory analysis
Laboratory methods are often more precise but slow. NIR gives fast, continuous results that support process control, within the limits of its calibration. Note: "No Spectroscopy" in the source list is a glitch for NIR spectroscopy.