Validated method for the analysis of 22 illicit drugs and their metabolites via liquid chromatography tandem mass spectrometry (LC-MS/MS) in illicit drug samples collected in Chicago, IL

•An LC-MS/MS method was developed for 22 illicit drugs and cutting agents.•The method was applied to 124 samples collected on paper cards at harm reduction sites in Chicago.•LC-MS/MS results showed a high frequency of fentanyl, heroin, and diphenhydramine in collected samples.•Fentanyl test strips detected fentanyl accurately in 95% of samples.