Fourier transform infrared data processing

Davies, A. M. C., S. M. Ring, J. Franklin, A. Grant, and W. F. McClure. 1985. Prospects of process control using Fourier transformed infrared data. Proceedings of the 1985 International Conference on Fourier and Computerized Infrared Spectroscopy. Ottawa (June 24—28). 

Fourier transform infrared (FTIR) spectroscopy is the most popular method for determining the imidization process in the solid state and identifying specific substituents on the macromolecular backbone (e.g., CN, SO3H, CO, SO2).131 A method for calculating the diermal imidization extent based on FTIR data has been reported by Pride.132 Raman spectroscopy was used on the model study of PMDA-ODA condensation, and the possible formation of an inline bond by reaction of an amino group with an imide carboxyle was evidenced.133... 

The SNIFTIRS approach. The acronym SNIFTIRS means Subtractively Normalized Interfacial Fourier Transform Infrared Spectroscopy. The basic concept of this method involves the fact that the raw data obtained directly from the Fourier Transform process contain components which are undesirable. Firstly, there is material in the solution which may have affected the spectrum. Secondly, unwanted information on certain material on the electrode (adsorbed water, for example) is best eliminated. 

A Fourier transform infrared spectroscopy spectrometer consists of an infrared source, an interference modulator (usually a scanning Michelson interferometer), a sample chamber and an infrared detector. Interference signals measured at the detector are usually amplified and then digitized. A digital computer initially records and then processes the interferogram and also allows the spectral data that results to be manipulated. Permanent records of spectral data are created using a plotter or other peripheral device. 

To shed light on the mechanism of formation of silsesquioxane a7b3, to identify the species formed during the process, and to try to explain the high selectivity towards structure a7b3 of the optimised synthetic method described above (64% yield in 18 h), the synthesis of cyclopentyl silsesquioxane a7b3 was monitored by electrospray ionisation mass spectrometry (ESI MS) [50-52] and in situ attenuated total reflection Fourier-transform infrared (ATR FTIR) spectroscopy [53, 54]. Spectroscopic data from the latter were analysed using chemometric methods to identify the pure component spectra and relative concentration profiles. 

Gillette PC, Lando JB, Koening JL (1985) A survey of infrared spectral data processing techniques In Ferraro JR, Basile LJ (eds) Fourier transform infrared spectroscopy -applications to chemical systems, Vol 4 Academic Press, New York, 1-47 Graham JA, Grim WM III, Fateley WG (1985) Fourier transform infrared photoacoustic spectroscopy of condensed-phase samples, In Ferraro JR, Basile LJ (eds) Fourier transform infrared) spectroscopy - applications to chemical systems, Vol 4 Academic Press, New York, 345-392... 

In most fields of physical chemistry, the use of digital computers is considered indispensable. Many things are done today that would be impossible without modem computers. These include Hartree-Fock ab initio quantum mechanical calculations, least-squares refinement of x-ray crystal stmctures with hundreds of adjustable parameters and mar r thousands of observational equations, and Monte Carlo calculations of statistical mechanics, to mention only a few. Moreover computers are now commonly used to control commercial instalments such as Fourier transform infrared (FTIR) and nuclear magnetic resonance (FT-NMR) spectrometers, mass spectrometers, and x-ray single-crystal diffractometers, as well as to control specialized devices that are part of an independently designed experimental apparatus. In this role a computer may give all necessary instaic-tions to the apparatus and record and process the experimental data produced, with relatively little human intervention. 

With the advancement of online measurement techniques such as focused beam reflectance measurement (FBRM) and Fourier transform infrared (FTIR), it is now possible to obtain particle size distribution and solution concentration information rapidly through these in-situ probes. In one experiment, hundreds of data points can be generated. With proper experiment design, the model-based experimental design for crystallization is capable of obtaining high-quality crystallization kinetic data with a small number of experiments. This approach can thus save significant experimental effort and time in the development of crystallization processes. 

Different apparati with different characteristics can be used for the same analytical method. Sometimes apparati manufactured in the same factory register differences in characteristics. The differences can be due to construction modifications and to the ambient conditions where the apparatus functions, which explains the differences between results obtained using the same apparatus in different laboratories. An example was demonstrated for the Fourier transform infrared (FT-IR) spectrometry technique that was applied for the analysis of aqueous solution.209 After the same aqueous solution determination in various laboratories by different workers with different instruments was produced by FT-IR technique, similar quality analytical information resulted using the same data processing simple linear method calibration. The conclusion is that the FT-IR spectrometer can be unstable... 

Fourier Transform Infrared (FT-IR) Spectroscopy is one of the most versatile techniques available for providing analytical data on the raw materials, the process chemistry and the products. Dispersive infrared spectroscopy has traditionally been an important tool in fuel characterization since most organic and mineral components absorb in the IR. Discussions of applications to coal may be found in Lowry (1 ), van Krevlen (2 ), Friedel O), Brown (O, Brooks, Durie and Sternhell ( 5) Friedel and Retcofsky (O and references cited therein. But FT-IR with its advantages in speed, sensitivity and data processing has added new dimensions. 

The conventional thermoanalytical techniques (thermogravimetry TG, differential scanning calorimetry DSC, differential thermal alysis DTA, etc.) can provide fundamental data concerning the thermal behaviour of these substances, but the addition of mass spectrometry (TG-MS) or Fourier transform infrared spectroscopy (TG-FTIR) has permitted the identification of gaseous species evolved during thermal processes. 

Fourier transform infrared (FTIR) spectroscopy is a powerful and reliable technique that for many years has been an important tool for investigating chemical processes and structures. In the polymer fields, FTTR data is used in order to study characterization of chemical bonds, polymer microstructure, chain conformation, polymer morphology, crystallinity and etc, consequently is useful in SPR studies. 

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