Petroleum products and lubricants are routinely analyzed for their elemental content. Before use, products like lubricating oils are tested to determine the concentration of additives (which contain metals such as calcium, copper, magnesium, phosphor, sulfur, and zinc) as this is an important quality control parameter. The concentrations of silicon, aluminum, vanadium, nickel, iron, and sodium in crude and residual oils are used to define their quality and value. High amounts of nickel and vanadium in crude oil can deactivate catalysts during processing, but also initiate corrosion in motors and boilers during combustion when present in fuels. Silicon and aluminum present in residual fuel oils cause abrasion within the combustion engine.
Trace metal analysis is also often performed to protect the environment: Waste products from refineries, such as waste waters and sludge, have to be investigated to determine how to dispose of them correctly. Prior to analysis via modern techniques such as ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) or ICP-MS (Inductively Coupled Plasma Mass Spectrometry) samples have to be transferred into a measurable, liquid form. This article summarizes the options for the sample preparation of petroleum products prior to trace metal analysis.