Simple Inorganic Ions Research Articles

H2O-D2O solvent isotope effects in the volume and expansivity behaviour of some organic and inorganic ions

Changes of structure of the water solvent caused by organic and inorganic ions have been investigated by measurements of the H2O-D2O solvent isotope effect in the partial molar volumes text-decoration:overlineV2 of alkali halides, tetraalkylammonium (TAA) and other ammonium type salts over a range of temperatures. The structure promoting hydrophobic ions have larger text-decoration:overlineV2 in D2O than in H2O, while the more electrostricting simple inorganic ions have smaller volumes in D2O than in H2O. By means of an extrapolation procedure based on the additivity of text-decoration:overlineV°2 for homologous TAA salts, the individual ionic contributions to the solvent isotopic volume difference can be evaluated. On this basis, the results indicate that the anions are predominantly the species that are associated with the so-called structure breaking effects in the simple salt solutions while K+ and the TAA cations exhibit an opposite kind of behaviour . The solvent isotope effect in text-decoration:overlineV2 for pyridine and H (as HOD) is also evaluated. Studies over a range of temperature enabled the partial molal expansibilities to be evaluated in H2O and D2O.

Photocurrents Produced by Ultraviolet Irradiation of Mercury Electrodes: II . Factors Influencing Photocurrents Caused by Electron Emission

The influence on the photocurrent of factors such as wavelength, scavenger concentration, ionic strength, diffusion coefficient of the hydrated electron, and the nature of products of the scavenging reaction, is considered. The discussion is illustrated by experimental data obtained by a variety of methods, and some preliminary results for substantially monochromatic light are described which lead to approximate relative rate constants for the scavenging of hydrated electrons by some simple inorganic ions and molecules.

THE SECRETION OF CRYSTALLOIDS AND PROTEIN MATERIAL BY THE PANCREAS IN RESPONSE TO SECRETIN ADMINISTRATION

The concentrations of sodium, potassium, calcium, chloride, bicarbonate, and protein and non-protein nitrogen were determined in series of samples of pancreatic juice secreted by dogs in response to (a) constant rate of administration of secretin, (b) varied rate of administration of secretin, and (c) interrupted administration of secretin (rest period, 2 hr.). Spectroscopic as well as chemical methods were used in the analysis of the samples.The data indicate that the membranes of the pancreatic gland offer little resistance to the passage of simple inorganic ions. The compensatory relation between the bicarbonate and chloride concentrations of the secretion is interpreted on the basis of (a) formation of at least part of the bicarbonate within the secretory cells, and (b) the action of membrane forces, probably of an electrical nature. Absorption spectrum studies indicate either (a) that only one type of absorbing protein is present in the secretion, or (b) that if several types are present, they are always secreted in constant proportions whether they are enzymatically active or not. The interpretation of the protein nitrogen and certain other data are given in a subsequent paper.