Quantitative Analysis of Mono- and Polybasic Benzene Carboxylic Acids in Potassium Bromide Disks by Infrared Spectroscopy

Nicholson, D E.

doi:10.1021/ac50164a019

Cited by 6 publications

(2 citation statements)

References 21 publications

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“…Gases are then adsorbed (via diffusion through the KBr matrix) onto the opaque materials, and the adsorbed species are studied by transmission IR spectroscopy. This KBr dilution method has long been recognized as a method for studying infrared spectra of solid compounds and surface modifications of solid materials before incorporation into the matrix. − However, this is the first known application of the technique for in situ transmission infrared studies of adsorption onto opaque surfaces while contained inside the supporting matrix.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Studies by Transmission IR Spectroscopy: A New Method for Opaque Materials

et al. 1999

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The study of adsorption on opaque powdered materials using transmission IR spectroscopy is described. The method involves diluting the optically dense adsorbent powder in solid KBr and then pressing the mixture into a tungsten grid. These thousands of tiny self-supporting samples make intimate contact with the grid array, allowing efficient thermal control of the sample temperature from 100 K upward. It has been found that gas adsorption may be studied on such samples by diffusion of the gas through the KBr matrix to the adsorption sites on the powder sample. Examples of the adsorption of small molecules, CO and CO2, on carbon surfaces and larger molecules, dimethylmethyl phosphonate and 2-chloroethylethyl sulfide, on a resin and an Al2O3 surface, respectively, are given, where KBr dilution opens up spectral regions that are not accessible in pure samples of the adsorbent. Interactional effects between the KBr support and the OH groups on Al2O3 are observed. A unique six-sample method for comparison of the adsorbent/KBr and pure KBr samples under identical conditions of gas pressure and temperature is described.

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Section: Introductionmentioning

confidence: 99%

Adsorption Studies by Transmission IR Spectroscopy: A New Method for Opaque Materials

et al. 1999

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“…Application of the alkali halide technique to the analysis of selected systems of the benzenecarboxvlic acids is discussed elsewhere (11); in general, the critical factor in obtaining quantitative analytical results via the potassium bromide method is careful control of the length of the grinding period. This control of grinding time appears to be the major means for securing good reproducibility in absorptivities through minimization of errors arising in potassium bromide from orientation effects, polymorphism, adsorption, the Christiansen effect, formation of mixed crystals, and other less well-defined phenomena.…”

Section: Methodsmentioning

confidence: 99%

Analyses of o-Xylene Oxidation Products

Lumpkin¹,

Nicholson²

1960

Anal. Chem.

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are outside these limits. Again, no explanation for the variations is available, The large variations occurred at the 50-p.p.m. level.Twelve 0.1-gram standard samples were run by the spectrographic method in laboratory E. The data were presented previously (B). As the spectrographic method relies on the use of standard samples, and because at that time there were no others available, a direct comparison between hydrogen extracted and hydrogen added was impossible. However, a plot of the log of the ratio of hydrogen-to-argon line intensities, /H6562A. to /6752A., VS. the log of hydrogen added gave a straight line through the data. From the line, it was possible to compare the results of any one sample with all the others if the spectrometer readings are assumed to be truly representative of the hydrogen contents of the samples. This assumption may not be valid as the technique was still in the development stage.The hydrogen values from the straight line are compared with the hydrogen added values in Table I. The data show that eight of the 12 samples agree with the spectrographic line to within 3%, while one falls outside this but is within 6%. Three values fall outside these limits. In general, this is a good indication that there is some degree of agreement between the standard samples and the spectrographic results. LITERATURE CITED

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Infrared Analysis of Pharmaceuticals I**Received October 30, 1959, from the Division of Pharmaceutical Chemistry, Food and Drug Administration, Washington 25, D. C.

Hayden

Sammul

1960

Journal of the American Pharmaceutical Association (Scientific

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Quantitative Analysis of Mono- and Polybasic Benzene Carboxylic Acids in Potassium Bromide Disks by Infrared Spectroscopy

Cited by 6 publications

References 21 publications

Adsorption Studies by Transmission IR Spectroscopy: A New Method for Opaque Materials

Adsorption Studies by Transmission IR Spectroscopy: A New Method for Opaque Materials

Analyses of o-Xylene Oxidation Products

Infrared Analysis of Pharmaceuticals I**Received October 30, 1959, from the Division of Pharmaceutical Chemistry, Food and Drug Administration, Washington 25, D. C.

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