Fourier Transform Infrared

Fourier Transform Infrared (FTIR) spectroscopy is an analytical technique that measures the absorption of infrared radiation by a sample across a broad range of wavelengths simultaneously, producing a molecular fingerprint spectrum used to identify chemical compounds, verify material composition, detect contaminants, and characterize functional groups within organic and inorganic substances. Unlike dispersive infrared instruments that scan wavelengths sequentially, FTIR instruments use an interferometer to collect all wavelength information at once, delivering faster measurement speeds and superior signal-to-noise ratios at equivalent measurement times.

The instrument core is a Michelson interferometer consisting of a broadband infrared source, a beam splitter — typically potassium bromide (KBr) or zinc selenide (ZnSe) — a fixed mirror, and a moving mirror driven by a precision linear actuator. As the moving mirror translates through its scan range, the interferometer modulates the intensity of each infrared wavelength at a unique frequency, producing an interferogram — a time-domain signal — that a fast Fourier transform algorithm converts into a conventional infrared absorption spectrum plotted as absorbance or transmittance versus wavenumber in cm⁻¹ across a range typically spanning 4,000 to 400 cm⁻¹.

Spectral resolution on benchtop FTIR instruments reaches 0.5 cm⁻¹ or better, with wavenumber accuracy maintained to ±0.01 cm⁻¹ through laser fringe referencing of mirror position. Attenuated total reflectance (ATR) accessories mount directly on the sample compartment, allowing solid, liquid, and viscous samples to be analyzed by direct contact with a diamond, germanium, or ZnSe internal reflection element without sample preparation or KBr pellet pressing.

Portable and handheld FTIR instruments extend measurement capability to field environments, enabling on-site identification of unknown chemicals, drug residues, explosive precursors, and counterfeit materials without laboratory sample transport.

In Pakistan, FTIR spectrometers are deployed in pharmaceutical quality control laboratories, forensic chemical analysis units, food adulteration testing facilities, polymer and materials characterization departments, environmental monitoring agencies, and customs and border control chemical identification operations.

Tactical Supply Pakistan supplies FTIR spectroscopy instruments across benchtop, portable, and handheld configurations for laboratory, forensic, and field analytical procurement across Pakistan.