After ten years of development and application ICP-MS has become a powerful anal. tool and is now being used routinely for trace element anal. in a wide variety of applications. While it cannot be said that the ICP-MS techniques is free from interference, progress will be made in overcoming both spectroscopic and nonspectroscopic interferences. Spectroscopic interferences relate to the spectral overlaps of many polyat. ions. Nonspectroscopic interferences, caused by major amts. of matrix elements in the samples under examn., generally result in suppression of the anal. signal. The limits of detn. are in the very low mg/g or, for some elements, in the sub mg/g region when analyzing dissolved steel samples at compromise operational conditions for multielement anal. In the iron and steel industry, ICP-MS is not limited to steel samples alone. Results are presented for the detn. of minor and trace amts. of elements in nonmetallic samples, i.e., slags.