Infrared spectroscopic method

The feasibility of using infrared laser beams for the monitoring of phosgene in and around the plant has been described [ICI47-ICI49]. Phosgene has strong absorption bands at 849 (r ) and 1827 cm (r,), but the combination band at 1011 cm (r +rj), is less than one thirtieth of the intensity of the 1827 cm band. The absorption data, appropriate to 

A method for the estimation of phosgene in commercial chlorine is based on a knowledge of the apparent extinction coefficient of the carbonyl stretching band in a high pressure cell designed to contain liquid chlorine [1664]. 

Vigerust and co-workers [1] used multivariate calibration methods to establish a new method for measurement of three additives in low-density polyethylene (LDPE). The determination of the concentrations of silica, erucamide and butylated hydroxyl toluene (BHT) is based on infrared spectroscopy and a calibration model compared to traditional methods - this method is both time- and cost-effective and is more precise. 

Reproduced with permission from B. Vigerust, K. Kolset, S. Nordenson, A. Henricsenand K. Kleveland, Applied Spectroscopy, 45,173. 1991, Society for Applied Spectroscopy, MD, USA [1], 

The results from the regression analysis are shown in Table 1.1. Best results were obtained for silica with a correlation coefficient (R ) of 0.99. For BHT the correlation coefficient was 0.84 and for erucamide 0.91. 

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Met. = Method. C = chronocoulometry, CC = corrosion current method, EC = Electrocapillary method, EL = Ellipsometric method, IR = Infrared spectroscopic method, CV = cychc voltammetry, RT = Radiotracer method, T = Tensammetry, TF = Thin film resistance, WL = weight loss method. When a combination of methods was used aU methods are listed separated by slashes. See also list of symbols. 

Both the infrared spectroscopic method and the polarographic method require special instruments. When instruments for both are available, the latter method seems to be preferred. Neither method has been found to be applicable to spray residues. 

Wakabayashi, F. and Domen, K. (1997) A new method for characterizing solid surface acidity - an infrared spectroscopic method using probe molecules such as N2 and rare gases. Catalysis Surveys from Japan 1 181. 

Kawahara [52-54] has described an infrared spectroscopic method applicable to essentially nonvolatile petroleum products. 

Therefore, for infrared spectroscopic methods, the total petroleum hydrocarbons comprise any chemicals extracted by a solvent that are not removed by silica gel and can be detected by infrared spectroscopy at a specified wavelength. The primary advantage of the infrared-based methods is that they are simple and rapid. Detection limits (e.g., for EPA 418.1) are approximately 1 mg/L in water and 10 mg/kg in soil. However, the infrared method(s) often suffer from poor accuracy and precision, especially for heterogeneous soil samples. Also, the infrared methods give no information on the type of fuel present in the sample, and there is little, often no information about the presence or absence of toxic molecules, and no specific information about potential risk associated with the contamination. 

M.J. Barajas, A.R. Cassiana, W. Vargas, C. Conde, J. Ropero, J. Figueroa and R.J. Romanach, Near-infrared spectroscopic method for real-time monitoring of pharmaceutical powders during voiding, Appl Spectrosc., 61(5), 490-496 (2007). 

N. Broad, P. Graham, P. Hailey, et al., Guidelines for the development and validation of near-infrared spectroscopic methods in the pharmaceutical industry. In Handbook of Vibrational Spectroscopy, vol. 5, J.M. Chalmers and PR. Griffiths (eds), John Wiley Sons Ltd, Chichester, 3590-3610, 2002. 

The infrared study of chemisorbed ammonia by Mapes and Eischens (55) was the first to demonstrate the power and utility of the infrared spectroscopic method for determination of surface acidity. These investigators demonstrated that IR spectra of ammonia chemisorbed on cracking catalyst contained H—N—H-bending bands that arose from NH4+ and coordinated NH3 (Fig. 6), a finding that constituted direct evidence for the existence of Br0nsted and Lewis acids on the surface of silica-alumina catalyst. Parry (23) subsequently suggested the use of pyri-... 

The infrared spectroscopic method is the same as the X-ray diffraction method, except that the infrared band absorptions are used instead of diffraction intensities. As in the X-ray analysis method, the dependence of the spectrum on temperature or on the presence of diluent can be used to determine which bands are due to the crystalline regions, and which to the amorphous. 

Arnold, S.A. Harvey, L.M. McNeil, B. etal., Employing near-infrared spectroscopic methods of analysis for fermentation monitoring and control. Part 1 Method development BioPharm Int. 2002, 15, 26-34, and Arnold, S.A. Harvey, L.M. McNeil, B. etal., Employing near-infrared spectroscopic methods of analysis for fermentation monitoring and control. Part 2 Implementation strategies BioPharm Int. 2003, 16, 47 19, 70. 

Budzinski et al. [142] have reported an infrared spectroscopic method for the determination of down to 200-300 ppb of semivolatiles such as polycyclic aromatic hydrocarbons and polychlorobiphenyls in soil. 

Infrared spectroscopic methods are extensively used to analyse polymers due to their simplicity, rapidity, reproducibility, non-destructive character and ease of sample preparation. Degree of crystallinity [73], chain branching [74], degree of oxidation [75], density measurements [76], quantification of additives [75, 77], end-group analysis [78, 79] and other physical/chemical properties have been studied using MIR and/or NIR. 

Fourier-transform Raman and Fourier-transform infrared spectroscopic methods were adapted for the analysis of spironolactone and differentiation of its polymorphic forms [31,32],... 

A new rapid mid-infrared spectroscopic method called diffuse reflectance infrared Fourier transform spectra (DRIFTS), coupled with chemometrics, has been developed by Janik, Merry, and Skjemstad (1998) and routinely applied to rapidly screen and compare crime scene samples (Figure 1.1). Added to these rapid methods and techniques are the use of rapid mass and volume magnetic susceptibility methods, which should also always be used before moving to the more costly methods (Figure 1.1). Mineral magnetic techniques are a relatively recent development (post-1971) and have now become a very powerful and widely used research tool to characterize natural materials in landscapes (e.g., Thompson and Oldfield 1986). 

A group in Latvia and Russia [78] analysed microbial cell mass by a fairly simple classical infrared spectroscopic method, recording spectra of dried biomass embedded in potassium bromide pellets with a dispersive IR spectrometer. They could calibrate the evaluation for four major groups of cellular... 

The Use of Infrared Spectroscopic Methods in the Field of Heterogeneous Catalysis by Metal Oxides... 

I 3 The Use of Infrared Spectroscopic Methods Table 3.2 Typical oxygen atom vibrational modes for metal oxide structures. 

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