James E. O'Reilly

Direct Atomic Absorption Analysis of Powdered Whole-Coal Slurries

Abstract A procedure has been developed which permits the direct analysis of powdered whole-coal samples by atomic absorption or atomic emission methods using conventional instrumentation, thereby eliminating time-consuming ashing and sample-digestion procedures. Linear plots of the absorption signal intensity versus the elemental concentration of analyzed whole-coal samples were obtained for several elements. Preliminary results indicate this method is applicable for the estimation of both minor-level (eg., Fe and Ca) and trace-level (eg., Pb and Zn) constituents.

Electrochemical reduction of substituted pyrimidines in acetonitrile

Abstract Polarographic studies of several substituted pyrimidines were reinforced by the results from cyclic voltammetry, controlled-potential electrolysis, and spectrophotometric examination of electrolyzed solutions, as well as by the examination of model compounds. Pyrimidines substituted with non-reducible groups (amino, methyl) are reduced in a single, one-electron (1e), diffusion-controlled process, very similar to that for pyrimidine itself. Pyrimidine-4-carboxylic acid exhibits three reduction waves: a very drawn-out acid-reduction wave with unusual properties and at more negative potential, an adsorption prewave and a wave corresponding to the 1e reduction of the pyrimidine moiety, 2-Chloro-and 2-bromopyrimidine each exhibit two polarographic waves; the first, corresponding to irreversible scission of the carbon-halogen bond, has electrochemical properties quite different from those normally expected; the second is due to reduction of the electro-generated pyrimidine. Results are compared with those for the reduction of bromobutane, bromobenene, and 2-bromopyridine.

Prediction of the concentrations in rat tissues of the intravenous anaesthetic methohexital from a nonlinear pharmacokinetic model.

A nonlinear pharmacokinetic model that describes the tissue distribution of intravenous anaesthetics was evaluated against experimental values for methohexital in the rat. There was excellent agreement between experimental and theoretical values for brain tissue, and good agreement for blood and adipose tissue. Agreement for lean tissue was good if it was assumed that some adipose tissue was present in skeletal muscle. Agreement was poor for all other visceral tissues. The experimental results justify further development of this mathematical model for use in accounting for differences in tissue distribution of anaesthetics, especially under various physiological conditions.

On the correlation of the weight per cent ash of coals and their silicon content

Abstract The high-temperature ash levels of some typical American bituminous coals can be rapidly estimated with a median standard error of ≈1.7 wt% ash (absolute) by means of a simple rectilinear correlation of wt% silicon with wt% ash. Approximately equivalent correlations are obtained regardless of whether silicon content is determined by instrumental fast neutron activation analysis (FNAA), X-ray fluorescence (XRF), or slurry-injection atomic absorption spectrometry (SIAAS). In contrast to some earlier reports, logarithmic correlations do not produce improved estimates. Correlations are not significantly improved by selecting coals within one rank or from one geographical area.

Simultaneous Analysis of Respiratory Gases and Nitrous Oxide in Dental Patients

The simultaneous analysis of respiratory gases in the presence of nitrous oxide is described. The modified gas chromatographic technique used is especially applicable to dental situations where continuous monitoring is not necessary. It employs readily available equipment and does not involve interference with other dental procedures.