Lähiinfrapunatekniikka

Lähiinfrapunatekniikka, often abbreviated as NIR, refers to a spectroscopic technique that utilizes the near-infrared region of the electromagnetic spectrum, typically ranging from 700 to 2500 nanometers. This technology works by measuring the interaction of light in this wavelength range with a sample. When near-infrared light is shone onto a sample, certain molecular bonds absorb specific wavelengths. These absorption patterns are unique to the chemical composition of the sample and can be used for identification and quantification.

NIR spectroscopy is a non-destructive and rapid analytical method. It does not require sample preparation in many cases, making it highly efficient for at-line, on-line, and in-line process monitoring. The technique is sensitive to the presence of organic functional groups, particularly those containing C-H, O-H, and N-H bonds. These bonds exhibit characteristic overtones and combination bands in the NIR spectrum.

The instrumentation for NIR typically consists of a light source, a wavelength selector (like a monochromator or filters), a sample holder, and a detector. The collected spectral data is then processed using chemometric methods, such as principal component analysis (PCA) or partial least squares regression (PLS), to extract meaningful information.

NIR spectroscopy has found widespread applications across various industries. In the food industry, it is used for analyzing moisture content, protein, fat, and fiber. In pharmaceuticals, it aids in raw material identification, quality control, and tablet analysis. The agricultural sector employs NIR for grain quality assessment, and in the petrochemical industry, it is utilized for product characterization and process control. Its versatility, speed, and non-destructive nature make it a valuable tool for a wide range of analytical challenges.