Fourier transform infrared (FTIR) spectroscopy is a measurement technique for collecting infrared spectra. Instead of recording the amount of energy absorbed when the frequency of the infra-red light is varied (monochromator), the IR light is guided through an interferometer. After passing through the sample, the measured signal is the interferogram. Performing a mathematical Fourier transform on this signal results in a spectrum identical to that from conventional (dispersive) infrared spectroscopy.
The measurement of a single spectrum is faster for the FTIR technique because the information at all frequencies is collected simultaneously. This allows multiple samples to be collected and averaged together resulting in an improvement in sensitivity. Because of its various advantages, virtually all modern infrared spectrometers are FTIR instruments.
Perkin Elmer Spectrum GX FT-IR Microscope
The Perkin Elmer Spectrum GX is a single-beam, Michelson interferometer based, Fourier transform infra-red spectrometer. It has a dual level optical module that is sealed and desiccated. The system is configured with a mid-infra-red single source. MIR and FIR beamsplitters and DTGS detector kits allow the range 7000 to 50cm-1 to be covered with a maximum resolution of 0.3cm-1.
The Spectrum GX is a modular system and can accommodate up to four equivalent output beams. The spectrometer is configured with the AutoIMAGE microscope system which can operate in transmission or reflectance modes
All manual microscope operations including adjustments to aperture, focas and illumination are fully automated and controlled from the PC. It includes built-in 35W tungsten halogen illuminator, a motorised stage and a CCD video camera.
The medium beam MCT detector covers the range from 5500 to 550 cm-1. An ATR attachment with a micro germanium crystal with a range from 5500 to 600 cm-1 can be used for micro samples and ATR mapping for surface studies.