The use of a mixed-solvent system for the determination of calcium and zinc in petroleum products by atomic-absorption spectroscopy

Abstract

A mixed-solvent system that permits the use of inorganic compounds as standards has been applied to the determination of calcium and zinc in unused lubricating oils and automatic transmission fluids by atomic-absorption spectroscopy. By the incorporation of hydrochloric acid into the solvent system, it has been found possible to eliminate the systematic errors that may occur when an air-acetylene flame is used in the determination of calcium.

Results have been obtained for a wide range of unused lubricating oils and automatic transmission fluids and there is good agreement with those obtained by X-ray fluorescence and established Institute of Petroleum chemical procedures (I. P. 111/49T Method B and I.P. 117/66T Method B).