Why Sample Uniformity Affects NIR Results
NIR analysis depends on consistent interaction between light and the sample. In powders, grains, minerals, food ingredients, polymers, and blended materials, differences in particle distribution or composition can cause one reading to vary from another.
Poor homogenisation can lead to unstable spectra, weak repeatability, and inaccurate predictions. This is especially important when the property being measured is not evenly distributed through the sample, such as moisture, active ingredient content, contamination, or blend uniformity.
Homogenisation does not always mean intensive grinding or processing. The right approach depends on the sample and application. Mixing, controlled presentation, repeated scans, cup rotation, or representative subsampling may be enough to improve confidence. For quantitative NIR work, the calibration should reflect the same preparation and presentation used in routine testing.
Improving NIR Measurement Reliability
For more detail on the method, review PAS’s overview of Near Infrared Spectroscopy technology. To compare suitable instruments, explore PAS’s NIR analysers through Portable Analytical Solutions, or contact our team to discuss homogenisation, sample preparation, and accuracy requirements.