A spectrometer such as this is designed for the analysis of natural petroleum and synthetic base fluids, such as hydraulic fluids and fuels. The excitation source is specifically designed for the analysis of wear metal particles suspended in lubricating fluids. To perform an analysis, a small portion of oil is taken and introduced into the plasma via the rotating graphite disc electrode. The plasma instantaneously vaporizes the oil and particles, creating light in wavelengths characteristic only of those elements which are present in the lubricant base and the wear metal particles suspended in it. The light from the plasma is transmitted to a polychromator which disperses the light into its component wavelengths. The intensity of each wavelength is measured to determine the concentration of the elements present in the sample.