Fig. 2

Three FTS (two lots manufactured by BTNX, one lot manufactured by DanceSafe) were run following manufacturer guidelines with aqueous solutions of 5000 ng/mL of each of the drugs or drug metabolites. Each strip was dried, stored for a week, then extracted with 5 mL of water/methanol 9:1 with sonication. Analysis of the amount of drug or drug metabolite that was extracted from the strip into the water/methanol solution was performed as previously described [23]