Recording apparatus for measuring oxygen absorption

Summary Two sensitive but inexpensive electrical circuits have been described which translate change in mercury level in a manometer to an electromotive force of sufficient magnitude so that it may be applied to a standard d.c. potentiometric recorder. The recording manometer, when coupled with a simple closed system containing a small amount of lipid material and oxygen or air, can be adapted to determine continuously the cumulative absorption of oxygen by the oil or fat. The break-point, a measure of the stability of the sample, may be obtained from the resulting curve. The apparatus has been successfully employed to determine the oxidative stability of hydrogenated soybean oil, and because of the small amount of attention required, it should be readily adaptable to quality control of edible oil and fat products. The recording manometer should be useful also for measuring and recording pressure changes in other systems. Presented at the meeting of American Oil Chemists’ Society, New Orleans, La., April 17–20, 1955.