FTIRspektroskopiaa

FTIRspektroskopiaa is a spectroscopic technique used to obtain infrared spectra of samples, providing molecular fingerprints based on vibrational transitions of chemical bonds. In this method infrared radiation is directed at a sample, and the resulting absorption is recorded as an interferogram by an interferometer. A Fourier transform converts the interferogram into a spectrum of absorbance or transmittance versus wavenumber.

A typical FTIR instrument includes an infrared source, a beamsplitter, a Michelson-like interferometer, a sample compartment, a detector, and a computer for data processing. The common spectral range lies roughly from 4000 to 400 cm−1, with resolutions around 0.5–4 cm−1. Modern systems use detectors such as DTGS or MCT and can employ various sampling modes to accommodate different sample types.

Sampling methods include transmission, attenuated total reflectance (ATR), and diffuse reflectance techniques. ATR-FTIR is particularly convenient for solids and powders, requiring minimal sample preparation, while transmission is often used for liquids in cells and thin films.

Interpreting FTIR spectra involves associating absorption bands with molecular vibrations, enabling identification of functional groups and, by comparison with spectral databases, possible compounds. The technique is typically qualitative or semi-quantitative, with limitations arising from band overlap, sample moisture, and the need for reference spectra. Choice of sampling method and proper calibration influence accuracy and sensitivity.

FTIRspektroskopiaa finds broad applications in polymer science, pharmaceuticals, coatings, materials characterization, environmental analysis, forensics, and art conservation, where rapid, non-destructive molecular analysis is valuable.