Elemental Analysis of Waste Oils by Inductively Coupled Plasma Mass Spectrometry

Abstract

Environmental regulations specify the analysis of recycled oil for arsenic, cadmium, chromium, lead, and total halogens. Waste oils for disposal must be analyzed for arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. Inductively coupled plasma mass spectrometry (ICP-MS) is a multielement technique with sufficient sensitivity to determine most metals and some nonmetals at the parts-per-billion level. Direct aspiration of the sample after dilution in a suitable solvent eliminates the tedious and potentially dangerous acid digestion process and the loss of volatile elements. The heat generated in the plasma and the addition of oxygen in the gas streams aid the breakdown of complexes of metals and the destruction of the organic matrix. The detection limits in a multielement analytical batch for elements of high mass [>80 atomic mass units (amu)] approach 5 to 50 μg/m3 for undiluted samples. Elements of lower mass suffer from isobaric or polyatomic interferences, which degrade detection limits.