When it comes to elemental analysis of liquid and solid samples, the two leading techniques are Inductively Coupled Plasma with Optical Emission Spectroscopy (ICP-OES) and X-Ray Fluorescence (XRF). The decision to use one technique over another is not always straightforward, as they both have significant advantages and limitations that must be considered on a case-by-case basis. The range of trace elements to be analyzed, and their concentration, will sometimes point to the most suitable technique, but there are many cases where the techniques overlap and several other factors must be considered to make the best choice. For example, there are significant differences in the actual running of the analyses that need to be considered, such as sample preparation, safety and health considerations, total analysis time, operator skill requirements, and accuracy and precision.

This article discusses several applications for ICP-OES and XRF, compares state-of-the-art instruments for both techniques, and offers a pathway for making well thought-out decisions when having to make a choice.