The Effect of Viscosity Index Improvers on the Determination of Zinc Using Atomic Absorption Spectroscopy

Atomic Absorption Spectroscopy is widely used in the petroleum industry for determination of the zinc concentration of new engine oils. Many of the methods in use rely on dilution of the sample with kerosene followed by aspiration into the AA.

It has been shown that such methods are subject to matrix interferences from other additive components.

One previously identified interferent is the VI improver included in the lubricant formulation.

This study is directed at determining the cause of the VI improver generated interference.

Included in the study is an examination of the effects of different chemical type and molecular weight polymers. Also included is a comparison of dispersant and non-dispersant VI improvers of similar molecular weight.

Some potential methods of eliminating the interference are also examined.