Pretreatment in the Determination of Trace Copper and Iron in Transformer Oil

Abstract

Comparative trace copper and iron analysis of unused and running transformer oil is performed by iCP-MS with pretreatment by ashing, acid dissolution and direct injection method. The advantages and drawbacks of each of the listed methods are discussed. The direct injection method is so simple and time-consuming that can realize accurate determination of copper in oil, while it is not suitable for determination of iron in used transformer oil. Although limited by availability of equipment, acid dissolution method has good accuracy and reproducibility for the determination of transformer oil in all states.