Why you should control temperature for more accurate and reproducible NIRS results

Near-infrared spectroscopy is an analytical method based on the interaction of light and matter. NIR spectrometers measure the absorption of light from the sample in the NIR region at wavelengths between 780 to 2500 nm. Results are fast and no sample preparation or chemicals are required.

Unfortunately, the effects of temperature variation on NIR measurements and its detrimental influence on accuracy and repeatability aren’t always immediately apparent. This is because temperature fluctuations typically occur over extended periods and aren’t noticeable during the initial state of developing applications and creating NIR prediction models.

To negate the effects of temperature variation, you can heat the sample holder to the target temperature and use a defined waiting time to ensure thermal equilibrium. Unfortunately, determining the ideal waiting time to ensure the sample reaches the target temperature while leveraging the speed of NIR analysis is challenging. One of the reasons being the starting temperature of the sample can be influenced by seasonal effects.

A more sophisticated approach is to monitor the sample temperature. The OMNIS NIR Analyser is great for such monitoring due to the combination of multiple temperature sensors and a sophisticated algorithm. With the OMNIS NIR Analyser, temperature-controlled measurements can be defined to evaluate and regulate sample temperatures automatically before the measurement begins. This eliminates waiting times, ensures target temperature is reached while maintaining a high analysis speed, and minimises temperature fluctuations.

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