William M. MacNevin

Separations of platinum metals by ion exchange : The separation of palladium from iridium2

Abstract Palladium and iridium are separated by passing an ammoniacal solution of the chlorides over Amberlite IR-100 resin. Palladium is retained as Pd(NH3)4+2 while iridium, as IrCl6-3, passes through the column quantitatively. Palladium is then removed from the column by elution with 1 M hydrochloric acid.

A chemical investigation of the lamprey eel venom.

Abstract The presence of a lipid, a carbohydrate, and a protein were shown in the lamprey eel venom. The protein was dried and its nitrogen content was determined. The ammoacids of the protein were determined qualitatively by means of paper chromatography, and a quantitative determination of the amino acids was done by ion-exchange chromatography.

The separation of mercury from gold by ion exchange

Mixtures containing large amounts of gold and small amounts of mercury (50:1) can be quantitatively separated by passing a 2N hydrochloric acid solution of the chlorides through Dowex 50 resin. Mercury behaves as a cation and is quantitatively retained. Gold behaves as an union and is not retained by the resin. The gold is obtained spcctrobcopically free from all metals. The capacity of the resin is approximately 10 nig of mercury per gram of rebin. The rcyin is freed from mercury by washing with 2N liydroclonc acid and may be used over again.

Analytical chemistry and the non-analytical graduate student

The present article is a plea for the inclusion of more analytical training for the non-analytical Ph.D. student.

Area effects in aluminum electrodes

Summary Potential differences and current flow have been observed between two aluminum electrodes of different sizes (areas) in solutions of dilute acetic acid containing small amounts of fluoride. The smaller electrode is regularly the anode. Reduction of the size of the larger electrode until it is the smaller reverses the polarity. Impurities and geometric shape of the electrodes have no detectable influence. Extensive oxidation, reduction and exposure to ultrasonic energy desensitize the electrode function. Air-equilibrated surfaces show a maximum response. Dissolved oxygen in the electrolyte has a small damping effect upon the response. Sensitivity is greatest in the p h range 2.5–4.5. Each electrode is found to have non-uniform distribution of potential and is more anodic in regions adjacent to surface coatings of wax, etc. Dependence of a mechanism upon participation of the oxide layer is indicated.