Fourier transform infrared computer system

D Commercial COTS controlled by external computer Hybrid systems such as automated dissolution workstation with high-performance liquid chromatography (HPLC) or ultraviolet-visible (UV-Vis) interface Liquid chromatographs, gas chromatographs, UV/Vis spectrophotometers, Fourier transform infrared (FTIR) spectrophotometers, near-infrared (NIR) spectrophotometers, mass spectrometers, atomic absorption spectrometers, thermal gravimetric analyzers, COTS automation workstations... 

Fourier transform infrared spectroscopy (FT—IR) has been developing into a viable analytical technique (56). The use of an interferometer requires a computer which increases the cost of the system. The ability of IR to differentiate geometrical isomers is still an advantage of the system, and computer techniques such as signal averaging and background subtraction, improve capabilities for certain analyses. 

The ultimate selectivity of gas chromatography is determined by the detector. The most selective detectors are spectroscopic, such as Fourier-Transform Infrared or Mass Spectrometer. Automated systems can employ chemometric algorithms to discriminate unresolved chromatographic peaks. These combinations are expensive and require significant computer support. As such, they are more likely to be used in a laboratory for confirmation. Efforts to convert this approach to field units are still under development. The MiniCAMS described above, based on a FPD is a reliable monitor but requires 3-5 min to make a determination. Gas chromatographs also require a source of purified gas for operation and the flame detector requires additional hydrogen and air for operation. This device will have the fewest false positives and the most... 

Ferraro JR, Basile LJ (1978) Fourier transform infrared application to national problems In Ferraro JR, Basile U (eds) Fourier transform infrared spectroscopy - applications to chemical systems, Vol 4 Academic Press, New York, 275-302 Ferraro JR, Rein AJ (1985) Application of diffuse reflectance spectroscopy in the far-infrared region In Ferraro JR, Basile LJ (eds) Fourier transform infrared spectroscopy -applications to chemical systems, Vol 4 Academic Press, New York, 244-282 Frank IE, Feikema J, Constantine N, Kowalski BR (1984) Prediction of product quality from spectral data using the partial least squares method J Chem Inf Comput Sci 24 20-24 Fuller MP, Griffiths PR (1980) Infrared microsampling by diffuse reflectance Fourier transform spectrometry Appl Spectrosc 34 533-539... 

Even worse in this respect is the introduction of computer-controlled instrumentation in the laboratory. Assuming the computer that drives the instrument is an IBM-compatible (many aren t), which compatible is it An XT A 286 AT A 386 A DOS or OS/2 operating system And then there s the software that drives the instrument. Is it all mouse-driven What keystrokes mean what I use a Mattson Galaxy model 2020 Fourier transform infrared (FTIR) instnunent. I m familiar with the Perkin-Elmer model, too. These two models look different, their computers are different, and their software is really different. I can t justify to myself the inclusion of one model over another because they are so different. (Yes, I have a Perkin-Elmer 710B as an example of a dispersive instrument, but dispersive instruments have more things in common than FTIR s.) So, unless someone has a really good approach and would like to tell me about it. I ll just have to think about it a bit more. 

Fourier transform infrared (FT-IR) spectroscopy is now one of the most popular techniques in analytical chemishy, this technology having several advantages compared to conventional dispersive infrared inshuments. Developments in instrument hardware, in computer software (usually by the instrument manufacturers) and in computing power generally has resulted in very powerful data collection and data handling systems for the analysis and characterisation of all sorts of materials including colorants. 

Infrared spectrophotometry is a familiar established analytical technique which provides identification of compounds by fingerprint spectra, of which a vast library is available. Both liquid and gaseous samples may be easily analysed and therefore modifications of established sample handling techniques have enabled both GC and HPLC instruments to be readily interfaced. Ideally, scan times of less than 1 s are required to be able to record each peak and peak shoulders. Instrument sensitivity is sufficient so that on the fly recording of spectra can be obtained from GC and HPLC eluants which contain nanograms of sample per ml mobile phase, for example, 10 ng sample in 100 pi GC-IR sample cell. Fourier transform infrared (FTIR) instruments are able to meet these criteria but until recently the instrumentation and computer system have been too expensive for routine use. The new generation of... 

The older, conventional instruments are known as dispersive spectrometers, where the infrared radiation is divided into frequency elements by the use of a monochromator and slit system. Although these instruments are still in use today, the recent introduction of Fourier transform infrared (FT-IR) spectrometers has revitalized the field (4). The FT-IR system is based on the Michelson interferometer. The total spectral information is contained in an interferogram from a single scan of a movable mirror. There are no slits, and the amount of infrared energy falling on the detector is greatly enhanced. Together with the use of modem computer techniques, an entirely new breed of instrument has been created. 

Fourier Transform infrared system at four wavenumber resolution in double beam operation. Standard double precision computer software were used to present data properly scale expanded in absorbance form. 

Fourier transform spectroscopy technology is widely used in infrared spectroscopy. A spectrum that formerly required 15 min to obtain on a continuous wave instrument can be obtained in a few seconds on an FT-IR. This greatly increases research and analytical productivity. In addition to increased productivity, the FT-IR instrument can use a concept called Fleggetts Advantage where the entire spectrum is determined in the same time it takes a continuous wave (CW) device to measure a small fraction of the spectrum. Therefore many spectra can be obtained in the same time as one CW spectrum. If these spectra are summed, the signal-to-noise ratio, S/N can be greatly increased. Finally, because of the inherent computer-based nature of the FT-IR system, databases of infrared spectra are easily searched for matching or similar compounds. 

FTIR takes a completely different approach. The spectral data are acquired as an Interferogram (Figure 1) which must be transformed Into a plot of Intensity versus wavenumber or wavelength through the application of Fourier transform equations. Thus, the computer Is an Integral part of the system without which little useful Information could be obtained. FTIR has the following advantages over computerized dispersive Infrared spectroscopy ... 

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