A simple determination of the alloy class can usually be accomplished using WDXRF without the need for matched standards by simply using Fundamental Parameters (FP), a “standardless” method relying on instrument sensitivity factors derived from pure elements. Table 1 shows results from three stainless steel alloys analyzed by this method. The measured compositions can be subsequently compared to known alloy specifications to confirm the particular alloy identity. Three very similar 300 series stainless steels (301, 303, and 304) were clearly distinguished and identified from the combination of their Ni and Cr concentrations. Trace elements with concentration specifications, such as sulfur and phosphorus, can similarly be used to identify a particular alloy. Additionally, the results from two aluminum alloys, 5052 and 6061 show accurate quantification to enable the alloy identification (Table 2). XRF has the ability to measure matrix compositions as well as trace elements to provide a nearly full survey; however, the C, N, and O concentrations are best measured by IGA, which complements the XRF results. The accuracy of the FP algorithm is enhanced with WDXRF measurements due to the very high energy resolution and low backgrounds associated with the technique.