Potassium bromide spectrum

IR spectra can be recorded on a sample regardless of its physical state—solid liquid gas or dissolved m some solvent The spectrum m Eigure 13 31 was taken on the neat sample meaning the pure liquid A drop or two of hexane was placed between two sodium chloride disks through which the IR beam is passed Solids may be dis solved m a suitable solvent such as carbon tetrachloride or chloroform More commonly though a solid sample is mixed with potassium bromide and the mixture pressed into a thin wafer which is placed m the path of the IR beam... 

Infrared spectra for solid organic compounds are frequently obtained by mixing and grinding a small sample of the material with specially dry and pure potassi um bromide (the carrier), then compressing the powder in a special metal die under a pressure of 15 30 tonnes to produce a transparent potassium bromide disc. As the potassium bromide has virtually no absorption in the middle-infrared region, a very well-resolved spectrum of the organic compound is obtained when the disc is placed in the path of the infrared beam. 

Test 2. According to the general method (2.2.24), examine miconazole by infrared absorption spectrophotometry, comparing with the spectrum obtained with miconazole CRS. Examine the substance as discs prepared using potassium bromide R. 

Test 1. Carry out the infrared test according to the general procedure <197 K>. The infrared absorption spectrum of a potassium bromide dispersion of it, previously dried, exhibits maxima only at the same wavelength as that of a similar preparation of USP miconazole RS. 

Transfer a portion of topical powder, equivalent to about 100 mg of miconazole nitrate to a 50 mL beaker, disperse in 40 mL of methanol, and mix for a minimum of 5 min. Allow to settle for 5-10 min, and filter into 100-mL beaker. Evaporate on a steam bath to dryness. Dry the residue at 105 °C for 10 minutes the infrared absorption spectrum of a potassium bromide dispersion of the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Miconazole Nitrate RS. 

Test 2 Examine by infrared absorption spectrophotometry, according to the general procedure (2.2.24), comparing with spectrum obtained with primaquine diphosphate Chemical Reference Substance (CRS). Examine the substance as discs prepared as follows dissolve separately 0.1 g of primaquine diphosphate and the reference substance in 5 mL of water R, add 2 mL of dilute ammonia R and 5 mL of chloroform R and shake dry the chloroform layer over 0.5 g of anhydrous sodium sulfate R prepare a blank disc using about 0.3 g of potassium bromide R, apply dropwise to the disc 0.1 mL of the chloroform layer, allowing the chloroform to evaporate between applications dry the disc at 50 °C for 2 min. 

The infrared spectrum of dobutamine hydrochloride in a potassium bromide disk is given in figure 3. Major band assignments are as follows ... 

Figure 6 shows the infrared spectrum of halcinonide run as a potassium bromide pellet, using a Perkin-Elmer Model 621 infrared spectrometer. Below are the interpretations of various absorbances.19... 

Infrared Spectrum of Halcinonide, Potassium Bromide Pellet. See text for details. 

The infrared spectrum of hydralazine hydrochloride (Figure 1) was obtained with a Beckman IR-12 spectrophotometer. A mineral oil dispersion between potassium bromide plates was scanned from 420 to 4000 cm-1, and a thicker layer of the dispersion, supported on polyethylene film,... 

The infrared spectrum of hydralazine hydrochloride base in a potassium bromide dispersion (Figure 2) was recorded from 400 to 4000 cm-1, and the 200 to 550 cm-1 region was obtained from a mineral oil dispersion supported on polyethylene film. The spectra of potassium bromide dispersions of the base are qualitatively identical to those of mineral oil dispersions. The assignment of absorption bands in the spectrum of the base is similar+to that of the hydrochloride except for the presence of N-H stretch absorption in the latter. A spectrum of the base has been published (6). 

Figure 2. Infrared Absorption Spectrum of Hydralazine Base, Potassium Bromide Pellet and Mull.

The infrared spectrum of neamine sulphate (formerly called neomycin A) also as a potassium bromide dispersion is illustrated in Fig. 4. All spectra are of authentic material supplied by The Upjohn Company, Kalamazoo. 

The infrared spectrum of sodium valproate is presented in Figure 1. The spectrum was measured in the solid state as a potassium bromide dispersion The following bands (cm l) have been assigned for Figure 1 (1). 

Solid samples or solid extracts can be mixed and ground with potassium bromide (KBr),pressed to form a transparent pellet, and a spectrum obtained from the pellet (see C in Figure 14.3). There are gas cells for obtaining spectra of gases and many other methods for obtaining spectra from liquid and solid samples that are not as frequently used as these [13-17],... 

An important raw material for pharmaceutical formulations is polyethylene oxide because it is used in many and various products. Polyethylene oxide is a solid material purchased in bulk as a powder. Sampling technicians collect samples in glass bottles. In the laboratory, small portions are taken and mixed with potassium bromide for the purpose of producing a KBr pellet and obtaining the IR spectrum. The spectrum thus obtained is compared to a reference spectrum to confirm that the material is indeed polyethylene oxide. 

Normal glass will only transmit radiation between about 350 nm and 3 /rm and, as a result, its use is restricted to the visible and near infrared regions of the spectrum. Materials suitable for the ultraviolet region include quartz and fused silica (Figure 2.28). The choice of materials for use in the infrared region presents some problems and most are alkali metal halides or alkaline earth metal halides, which are soft and susceptible to attack by water, e.g. rock salt and potassium bromide. Samples are often dissolved in suitable organic solvents, e.g. carbon tetrachloride or carbon disulphide, but when this is not possible or convenient, a mixture of the solid sample with potassium bromide is prepared and pressed into a disc-shaped pellet which is placed in the light path. 

V band spect Absorption bands that appear in the ultraviolet part of the spectrum due to color centers produced in potassium bromide by exposure of the crystal at temperature of liquid nitrogen (81 K) to intense penetrating x-rays. ve. band ( vcp See vacuum condensing point. 

Procedure To the sample which contains 20-300 /xg of pertechnetate in 5-20 ml of solution, are added potassium perchlorate solution (2 ml, 1 mg KCIO per ml) and enough NaCl to make the solution approximately 1 M. The solution is heated and neutralized with ammonia. Pertechnetate is precipitated with aqueous 5 % tetraphenylarsonium chloride reagent. The precipitate is filtered, washed and dried, and a 2-mg portion is mixed with potassium bromide (300 mg). The mixture is pressed to form a clear disc by the usual technique. The infrared spectrum is recorded between 10 and 12 /x. The peak absorption is measured at 11.09 /X by the base-line technique. 

The infi red absorption spectrum of benzoic acid was obtained in a potassium bromide disc (using approximately 2 mg of benzoic acid dispersed in 200 mg KBr), and recorded on a Jasco 5300 FTIR spectrophotometer. The spectrum thusly obtained is shown in Figure 6, and the assignment of the characteristic bands is given in Table 3. 

The infrared spectrum, for a sample prepared as a potassium bromide pellet, is highly characteristic of the compound. The spectrum is shown in Figure 6 and Table 3 lists the band assigiunents. 

M. le Blanc gave the refractive indices of solii. of potassium and rubidium bromides as 1 5593 and 1 5533 respectively, when the densities are 2"738 and 3 314 respectively. Hence the refraction eq. of potassium bromide by Gladstone and Dale s formula is therefore 24 32 and by Lorentz and Lorenz s formula 14-05 the corresponding values for rubidium bromide are27"62 and 15"98. The mol. refractions of potassium bromide in soln. by the two formulae are respectively 25"11 and 14 70 and of rubidium bromide in soln., 27 85 and 16 33. The mol. refractions of these salts are therefore greater in soln. than in the solid form. Crystals of potassium bromide, says H. Marbuch, exhibit optical activity. A. S. Newcomer found that sodium chloride was the only salt relatively soluble and yet capable of emitting fluorescent rays in the mid-ultra-violet region of the spectrum under the influence of X-rays. 

The infrared spectra of the coal and the various extracts were recorded on a Baird, Model GY-1 (Ireland Mine vitrain concentrate) and on a Perkin Elmer Model 337 spectrophotometer (Bruceton coal). The samples were prepared by the potassium bromide pellet technique. The high resolution proton NMR spectrum of the benzene soluble extract from Ireland Mine vitrain concentrate was recorded on a Varian A-60 spectrometer in 10% deuterated chloroform (CDCh) solution, using tetrametnylsilane internal standard. 

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