Using a peak intensity threshold of 5 % relative intensity, step 1 of the ILSA identifies 8 peaks (targets) for compound matching and scoring. With the updated ILSA, which allows matching of targets with the expanded reference m/z lists, all Targets except 6 and 7 are easily identified. For example, Target 3 still matches several cathinone isomers with low scores, but also matches xylazine as an M+1 isomer with much higher scores than the cathinones. The identification of this target as the M+1 isomer of xylazine is further supported by an isotope ratio difference close to zero (0.14)-if a cathinone or another compound with a major ion at m/z 222 was in the mixture, this intensity ratio would be further from zero in the positive direction. A complete comparison of results using the original and updated ILSA is provided in Table . Additionally, summary head-to-tail plots comparing the potential library match spectra to the mixture spectra are provided as Figures S1 through S3 of the Supplemental material.