Fourier transform infrared detection

Principles and Characteristics Fourier-transform infrared detection in SFC is attractive because it can offer structural information about the analytes [372]. The coupling was introduced in 1983 [373]. Various approaches have been advanced ... 

While HPLC does not always produce superior results to those with TLC it allows greater versatility and is more suitable for the analysis of complex organic matrices such as cereals. HPLC coupled to sensitive detection and sophisticated data retrieval has improved the identification of selected mycotoxins at levels much less than achieved by TLC. Additional chromatographic modes such as normal-phase, reverse phase and ion-exchange chromatography have been employed. There are no truly universal detectors available for HPLC. Detectors presently in use include Fourier transform infrared detections (FT-IRD), diode array ultraviolet detection (DAD) and mass selection detectors (MSD) (Coker, 1997). 

Purge-and-trap techniques in which volatile analytes are evolved from blood or urine in a gas stream and collected on a trap for subsequent chromatographic analysis have been developed. Such a technique employing gas chromatographic separation and Fourier transform infrared detection has been described for a number of volatile organic compounds in blood.6... 

Lendl, B., Schindler, R., Frank, J., Kellner, R., Drott, J., Laurell, T., Fourier transform infrared detection in miniaturized total analysis systems for sucrose analysis. Anal. Chem. 1997, 69(15), 2877-2881. 

Tsuda, T., Aoki, M., Kojima, M., Fujita, T. (1993) Accumulation and excretion of chloroanilines by carp. Chemosphere 26, 2301-2306. Tuazon, E.C., Winer, A.M., Pitts, J.N., Jr. (1978) Fourier transform infrared detection of nitroamines in irradiated amine-NOx systems. 

Many other on-line detectors suitable for SEC columns as reviewed [154], including chemiluminescent nitrogen detection, dynamic surface tension detection, high frequency detection and Fourier transform infrared detection, can be applied to FFF the latter being capable of delivering polymer compositions online. 

Bartle, K.D., M.W. Raynor, A.A. Clifford, I.L. Davies, J.P. Kithinji, G.F. Shilstone, J.M. Chalmers, and B.W. Cook. 1989. Capillary supercritical fluid chromatography with Fourier transform infrared detection. J. Chromatogr. Sci. 27 283-292. 

Bush, B. and E.L. Barnard. 1995. Gas phase infrared spectra of 209 polychlorinated biphenyl congeners using gas chromatography with Fourier transform infrared detection internal standardization with a 13C-labelled congener. Arch. Environ. Contam. Toxicol. 29 322-326. 

D. K. Morgan, N. D. Danielson, and J. E. Katon, Aqueous Flow Injection Analysis with Fourier Transform Infrared Detection. Anal. Lett., 18 (1985) 1979. 

Supercritical Fluid Chromatography with Fourier Transform Infrared Detection... 

Vonach, R., Lendl, B., and Kellner, R., High-performance liquid chromatography with real-time Fourier-transform infrared detection for the determination of carbohydrates, alcohols and organic acids in wines, /. Chromatogr. A, 824, 159, 1998. 

Kolhed, M., Hinsmann, R, Svasek, R, Fraiik, J., Karlberg, B., and Lendl, B., On-line fourier transform infrared detection in capillary electrophoresis, AncU. Chem., 74, 3843, 2002. 

Lendl B, Schindler R, Frank J, Kellner R, Drott J, Laurell T (1997) Fourier transform infrared detection in miniaturized total analysis systems for sucrose analysis. Anal Chem 69 2877-2881 Lenshof A, Ahmad-Tajudin A, Jaras K, Sward-Nilsson AM, Aberg L, Marko-Varga G, Malm J, Lilja H, Laurell T (2009) Acoustic whole blood plasmapheresis chip for prostate specific antigen microarray diagnostics. Anal Chem 81 6030-6037 Lin VSY, Motesharei K, Dancil KPS, Sailor MJ, Ghadiri MR (1997) A porous silicon-based optical interferometric biosensor. Science 278 840-843... 

Fourier transform infrared detection is now available for TLC. Many layers had high IR absorbance, and were inadequate for direct IR measurement. Presently, layers are available that allow direct measurement (63). No applications to nucleic acids have been reported. 

S Maeno, PA Rodriguez. Simple and versatile injection system for capillary gas chromatography columns performance evaluation of a system including mass spectrometry and light-pipe Fourier-transform infrared detection. J Chromatogr 731 201-215, 1996. 

Chemical Gas Detection. Spectral identification of gases in industrial processing and atmospheric contamination is becoming an important tool for process control and monitoring of air quaUty. The present optical method uses the ftir (Fourier transform infrared) interference spectrometer having high resolution (<1 cm ) capabiUty and excellent sensitivity (few ppb) with the use of cooled MCT (mercury—cadmium—teUuride) (2) detectors. 

Such effects principally cannot be observed in multi band detectors such as a UV diode array detector or a Fourier transform infrared (FTIR) detector because all wavelengths are measured under the same geometry. For all other types of detectors, in principle, it is not possible to totally remove these effects of the laminar flow. Experiments and theoretical calculations show (8) that these disturbances can only be diminished by lowering the concentration gradient per volume unit in the effluent, which means that larger column diameters are essential for multiple detection or that narrow-bore columns are unsuitable for detector combinations. Disregarding these limitations can lead to serious misinterpretations of GPC results of multiple detector measurements. Such effects are a justification for thick columns of 8-10 mm diameter. 

The use of detection methods sueh as mass speetrometry (MS) and Fourier-transform infrared (FTIR) speetroseopy ean be very useful with respeet to the quality... 

Table 5.8 Polypeptides detected during the LC-electrospray-MS analysis of the tryptic digest from / -lactoglobulin (/ILG). Reprinted from 7. Chromatogr., A, 763, Tnrnla, V. E., Bishop, R. T., Ricker, R. D. and de Haseth, J. A., Complete structnre elncidation of a globular protein by particle beam hqnid chromatography-Fourier transform infrared spectrometry and electrospray hqnid chromatography-mass spectrometry - Seqnence and conformation of / -lactoglobulin , 91-103, Copyright (1997), with permission from Elsevier Science...

The availability of the purified transporter in large quantity has enabled investigation of its secondary structure by biophysical techniques. Comparison of the circular dichroism (CD) spectrum of the transporter in lipid vesicles with the CD spectra of water-soluble proteins of known structure indicated the presence of approximately 82% a-helix, 10% ) -turns and 8% other random coil structure [97]. No / -sheet structure was detected either in this study or in a study of the protein by the same group using polarized Fourier transform infrared (FTIR) spectroscopy [98]. In our laboratory FTIR spectroscopy of the transporter has similarly revealed that... 

Figure 5.11 (Crisp Wilson, 1974b) shows the time-dependent variation of the concentration of soluble ions in setting and hardening cements. Note that the concentrations of aluminium, calcium and fluoride rise to maxima as they are released from the glass. After the maximum is reached the concentration of soluble ions decreases as they are precipitated. Note that this process is much more rapid for calcium than for aluminium and the sharp decline in soluble calcium corresponds to gelation. This indication is supported by information from infrared spectroscopy which showed that gelation (initial set) was caused by the precipitation of calcium polyacrylate. This finding was later confirmed by Nicholson et al. (1988b) who, using Fourier transform infrared spectroscopy (FTIR), found that calcium polyacrylate could be detected in the cement paste within one minute of mixing the cement. There was no evidence for the formation of any aluminium polyacrylate within nine minutes and substantial amounts are not formed for about one hour (Crisp et al, 1974).

Detection in SFC can be achieved in the condensed phase using optical detectors similar to those used in liquid chromatography or in the gas phase using detectors similar to those used in gas chromatography. Spectroscopic detectors, such as mass spectrometry and Fourier transform infrared spectroscopy, are relatively easily interfaced to SFC compared to the problems observed with liquid mobile phases (see Chapter 9). The range of available detectors for SFC is considered one of its strengths. 

Brown, R. S., Hausler, D. W., Taylor, L. T., and Carter, R. C., Fourier transform infrared spectrometric detection in size-exclusion chromatographic separation of polar synfuel material, Anal. Chem., 53, 197, 1981. 

Ludlow, M., Louden, D., Handley, A., Taylor, S., Wright, B., and Wilson, I.D., Size-exclusion chromatography with on-line ultraviolet, proton nuclear magnetic resonance, and mass spectrometric detection and on-line collection for off-line Fourier transform infrared spectroscopy, /. Chromatogr. A, 857,89,1999. 

Figure 7.10 Typical optical arrangements employed for detection of (a) vapour phase (b) liquid phase and (c) solid chromatographic phases. After White [167], Reprinted from R. White (ed.), Chromatography/Fourier Transform Infrared Spectroscopy and Its Applications Marcel Dekker Inc., New York, NY (1990), by courtesy of Marcel Dekker Inc.

Goodacre, R. Shann, B. Gilbert, R. J. Timmis, E. M. McGovern, A. C. Alsberg, B. K. Kell, D. B. Logan, N. A. Detection of the dipicolinic acid biomarker in Bacillus spores using Curie-point pyrolysis mass spectrometry and fourier transform infrared spectroscopy Anal. Chem. 2000,72,119-127. 

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