X-ray fluorescence analysis of additives and wear metals in used lubricating oils

The determination of metal concentrations in lubricating oils is a very important diagnostic development. Such analysis dates back over 50 years, when one of its earliest uses was to assess engine oil from trains. Today, the analysis of both new and used lubricating oils, as well as the monitoring of trends in the metal concentrations and additives they contain, has become an essential control. Since its origins, many methods have been employed for wear metal analysis. X-ray fluorescence spectrometry (XRF) quickly became established in the petrochemical industry for the analysis of sulphur, and the unique qualities of the technique - simple sample preparation, high accuracy and good to excellent detection limits across large parts of the periodic table - mean that XRF is also a powerful tool for the analysis of wear metals in lubricating oils. In this article we report on data obtained using a new package, Oil-Trace (PANalytical), in the XRF analysis of four common additives and 13 wear metals in used lubricating oils.