Applied Spectroscopy

Woodriff, Ray

doi: 10.1366/000370274774332236pmid: N/A

Four types of atomization chambers for atomic absorption are reviewed. Advantages and disadvantages of each are considered. The effects of chamber dimensions and sample introduction system are considered in relation to accuracy, sensitivity, and convenience. Relative sensitivity is more significant for real samples than absolute sensitivity. When peak heights are measured, the relative sensitivity is proportional to the atomizer chamber length. When peak area is measured, the relative sensitivity is proportional to the third power of the atomizer chamber length.Matrix materials in general affect the accuracy of determinations by changing the rate or time of atomization. Matrix effects are less serious with long tight tubes than they are for tubes with openings near the center.

Wilson, H. William; Friedmann, Nadav

doi: 10.1366/000370274774332092pmid: N/A

The infrared spectra of crystalline 1,2-, 1,3-, and 1,4-naphthalenediols in KBr or CsI pellets have been interpreted on the basis of a comparison with the spectra of other naphthalene derivatives. Assignments have been proposed for all but four vibrations which are expected to fall below 300 cm−1.

Condit, D. A.; Craven, S. M.; Katon, J. E.

doi: 10.1366/000370274774332083pmid: N/A

The infrared and Raman spectra of benzoyl chloride, benzoyl chloride-d5, and benzoyl bromide have been measured between 75 and 4000 cm−1. Assignments for the fundamental modes of vibration are presented.

Carter, James C.; Luther, George W.; Moyé, Alfred L.

doi: 10.1366/000370274774332209pmid: N/A

Low temperature infrared spectral data are given for the adducts H3BC(O)N(CH3)3, D3BC(O)N(CH3)3, H3BC(O)N(CD)3)3)D3BC(O)N(CD3)3 over the range 3000 to 300 cm−1. Boron-11 NMR data are given for H3BCO and H3BC(O)N(CH3)3. The spectra allow the assignment of the structure of the adducts as

Ahmed, A.; Gallei, E.

doi: 10.1366/000370274774332128pmid: N/A

A quantitative method for studying surface species by infrared spectroscopy has been described. The solid particles are not subjected to high pressures or contacted with any extraneous substance during sample preparation. The method is quantified by using the solid substrate as an internal standard. Reproducibility measurements on surface concentration of trimethylchlorosilane adsorbed on silica gel and Aerosil gave 3.29 and 3.49% standard errors, respectively. Quantitative measurement of surface hydroxyl groups in open systems is also described.

Bankston, Donald C.; Goldsmith, Roger A.

doi: 10.1366/000370274774332164pmid: N/A

A single computer program, for use in especially highly precise and accurate applications of the Walsh atomic absorption method, is designed to allow an analyst the freedoms (1) to determine the concentrations of up to 11 elements in an unrestricted number of samples; (2) to use up to 40 differently named standards and/or series of standards simultaneously, with or without a dilution option; (3) to fit any standard curve and associate it with either one equation or two; (4) to make the equation of all or part of any standard curve a polynomial of either first or second degree; and (5) to have standard curve equation coefficients and/or coordinates of certain points on the standard curve printed out in easily readable form. The concentration of a given element of interest, in any sample, is treated as a variable with random properties. Up to 26 estimates of this concentration can be made, and, from them, the program computes the mean, standard deviation, coefficient of variation, and both 95 and 99% confidence limits about the mean.

Wyatt, David M.; Gray, Robert C.; Carver, James C.; Hercules, David M.; Masters, Larry W.

doi: 10.1366/000370274774332146pmid: N/A

X-ray photoelectron spectroscopy (ESCA) has been used to identify very thin layers of polymeric species remaining on aluminum plates after the polymer was cured and stripped from the aluminum. Two polymers were studied. In one, the residual polymeric carbon was used as the tracing signal; in the other, the polymeric silicon was used. In both cases, the polymeric species was partially sputtered from the aluminum surface by an argon ion gun. A reduction in the polymeric signal relative to a standard signal was noted. The results of this study show that, when the polymers studied were mechanically pulled from the aluminum substrate, the failure was a cohesive separation within the polymer, rather than failure at the polymer-aluminum interface. Scanning electron microscopy was used to show that the residual polymer does not remain on the surface as “clumps” or “islands,” but rather as a smooth surface a few atomic layers thick.

Pathak, B. P.; Makherjee, S. K.

doi: 10.1366/000370274774332137pmid: N/A

The shapes of x-ray and γ-ray peaks have been studied with the use of a high resolution Ge(Li) spectrometer. The Kα x-ray peaks of high Z elements have been found to exhibit larger width compared to the width of γ-ray peaks of same energy. This excess width has been assigned to the natural energy width of characteristic x-ray lines. An analytical study of the variation of the observed width with the natural width of the incident radiation has been made. The computed results are in excellent agreement with the experimental observation.

Brachfeld, Bernard

doi: 10.1366/000370274774332191pmid: N/A

A method, employing x-ray fluorescence, is described for the determination of Al and WC in a heterogeneous Ni alloy powder. It is shown that using a Pitchford electric arc button furnace (model 701 BF) to melt the powder sample resulted in a homogeneous solid button only after a 60% addition of Ni was made to the original sample. Comparative data are presented for the determination of Al and WC by atomic absorption.

Cowgill, Ursula M.

doi: 10.1366/000370274774332245pmid: N/A

A new method is described, employing acetone and a sonicator, for the procurement of a homogeneous mixture of lake mud and graphite suitable for optical emission analysis. The effects of variable matrices are masked by use of a mixture of 2 parts graphite to 1 part CaF2. The elements studied in these variable matrices were Be, Hg, Bi, Sn, Co, B, Na, Mo, V, Ag, Li, and Cd. The percent standard deviations obtained on replicate analyses are extremely small.