METAL ANALYSIS BY SPECTROSCOPY
In addition to the naturally occurring metals in the crude oil and the petroleum products derived from it, certain metals are added as additives to lubricating oils and similar products. These metal additives act as detergents, antioxidants, antiwear agents, etc. Some of these additives contain one or more of these metals: boron, barium, calcium, copper, magnesium, molybdenum, phosphorus, zinc, etc. In used lubricating oils, several other metals may be present coming from the engine wear in addition to those from the additives. On the other hand, in certain petroleum products even trace amounts of metals may prove deleterious to engine performance. Hence, it is important to have test methods that can determine metals, both at trace levels and at major concentrations. Elsewhere in this guide, some specific test methods are described for the determination of specific metals such as lithium, manganese, sodium, etc. In this particular section, multielement methods using atomic spectroscopic techniques are described. In the current marketplace atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, and X-ray fluorescence spectroscopy have proved widely popular and highly useful.
