A major safety concern for pharmaceuticals and environmental samples is that extractable and leachable compounds could contaminate products that come into contact with consumers. This application note demonstrates how Wiley's KnowItAll software can be used to analyze LC-MS/MS spectra for the targeted search of known contaminants, as well as the untargeted search for unexpected ones. Combining targeted screening against the ELSIE E&L compound database with untargeted analysis using NIST MS/MS libraries, successfully identified a plasticizer extracted from a container during storage, which was confirmed by comparing results from both analytical methods and validating against a blank sample.