Double-beam infrared spectrophotometer

The schematic optical diagram of a double-beam infrared spectrophotometer has been shown in Figure 22.3 as per Beckman Model IR-9. 

Material - shall consist of the beta polymorph only as determined by the examination of a 5% muli of the sample in hexachlorobutadiene or tetrachloro-ethylene by means of a Perkin Elmer Double Beam Infrared Spectrophotometer, Model 21. The mull is prepd by grinding the sample one min in dry state and then adding hexachlorobutadiene and again grinding for another min. The spectrophotometer has a drum setting for th e slit of 980. This gives a slit of about 460 microns ac 13.5 microns and a... 

Procedure Use a suitable double-beam infrared spectrophotometer and matched 0.4-mm liquid sample cells with... 

It is very advantageous, of course, to be able to remove solvent absorption bands in a spectrum. In double-beam infrared spectrophotometers, atmospheric absorption bands are readily blanked out. These instruments can also be used to blank out solvent absorption bands, thus producing an unperturbed baseline. This is done by placing in the reference beam of the spectrophotometer another cell of matched optical path containing pure solvent. The low-intensity bands of carbon tetrachloride (Fig. 3.3) in a 0.1-mm cell are blanked out easily in this way. This is true for other solvents having some bands of low intensity (e.g., acetone at 2600 and 2000 cm S and dimethyl formamide at 1950 cm in 0.1-mm cells). 

L. J. Bellamy, Analysis with Double-Beam Infrared Spectrophotometers, J. Appl. Chem. 3, 421, 1953. 

I. A. Brownlie, Recording Double-Beam Infrared Spectrophotometer, J. Sci. Insir. 27, 215, 1950. 

D. F. Hornig, G. E. Hyde, and W. A. Adcock, Ratio-Recording Double-Beam Infrared Spectrophotometer with Automatic Slit-Control, J. Opt. Soc. Am. 40, 497, 1950. 

J. U. White, Double-Beam Infrared Spectrophotometer. Chemical and Biochemical Applications, Anal. Chem. 22, 768, 1950. 

Figure 23.3 Schematic Diagram of a Filter-Grating, Double-Beam Infrared Spectrophotometer. This diagram shows a scanning instrument. The wavelength passed is determined by the angular position of the grating, which is mounted on a turntable, and is rotated automatically by a motor. Courtesy of Perkin-Elmer Corporation.

Infrared spectra of the polymer, before and after photolysis, were run on a Perkin Elmer 521 double-beam grating spectrophotometer, using compression-molded films. Film thicknesses were determined by a micrometer. 

Infrared studies were carried out using a 337 Perkin-Elmer double beam grating spectrophotometer, and x-ray diffraction was carried out using a Philips x-ray diffraction analyzer system, PW 1840, using a Nickel-filtered Cu Ko radiation. A Thermolyne 48000... 

K. Kudo and T. Miyazaki, A Single-Beam Double-Path Infrared Spectrophotometer, Oyo Butsuri 24, 461-466, 1955. 

FIGURE 9 Conventional double-beam infrared absorption spectrophotometer. 

Figure 3.23 A typical double-beam recording mid-infrared and near-infrared spectrophotometer...

Pierre [60] has reported a study of the characterisation of the surface of oil slicks by infrared reflective spectroscopy. A double-beam spectrophotometer was modified for studying the reflectance spectra (at angles of incidence 45°, 60°, 70°) of oil layers (20-30 xm thick) on the surface of water using pure water as reference. 

Lambda 2 Ultraviolet-visible double-beam spectrophotometer Lambda 3 Ultraviolet-visible double-beam spectrophotometer Lambda 5 and Lambda 7 Ultraviolet visible spectrophotometers Lambda 9 Ultraviolet visible—near infrared spectrophotometer Lambda Array 3430 Spectrophotometer... 

Part—IV has been entirely devoted to various Optical Methods that find their legitimate recognition in the arsenal of pharmaceutical analytical techniques and have been spread over nine chapters. Refractometry (Chapter 18) deals with refractive index, refractivity, critical micelle concentration (CMC) of various important substances. Polarimetry (Chapter 19) describes optical rotation and specific optical rotation of important pharmaceutical substances. Nephelometry and turbidimetry (Chapter 20) have been treated with sufficient detail with typical examples of chloroetracyclin, sulphate and phosphate ions. Ultraviolet and absorption spectrophotometry (Chapter 21) have been discussed with adequate depth and with regard to various vital theoretical considerations, single-beam and double-beam spectrophotometers besides typical examples amoxycillin trihydrate, folic acid, glyceryl trinitrate tablets and stilbosterol. Infrared spectrophotometry (IR) (Chapter 22) essentially deals with a brief introduction of group-frequency... 

Recording spectrophotometers in the infrared, visible and ultraviolet regions necessarily employ the double-beam principle of operation (figures 9.1(a) and (b) and p. 274), but for quantitative measurements at fixed... 

Infrared spectra were recorded on a Perkin-Elmer Model 983G double-beam spectrophotometer in the transmission mode using 3500 A thick PBTMSS films spin-coated and processed on polished NaCl plates. Spectral subtraction and absorbance correction to account for the decreased film thickness were used to isolate the silicon oxide absorption band at about... 

Figure 10.7 Schematic diagram of spectrometers and analysers in the infrared, (a) Single beam analyser containing a fixed monochromator or a filter used when a measurement at a single wavelength will suffice (b) dispersive spectrometer, double beam system. In contrast to spectrophotometers in the UV/Vis, the sample, located prior to the monochromator is permanently exposed to the full radiation of the source, knowing that the energy of the photons in this region is insufficient to break the chemical bonds and to degrade the sample (c) Fourier transform single beam model.

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