The solid psilocybin (Psygen Labs, 99.977%) was stored in an airtight container without exposure to light at ambient temperature and otherwise used as received. A stock psilocybin solution was prepared by measuring and dissolving 0.0512 g of solid psilocybin weighed via analytical mass balance into 100.00 mL of deionized water measured with a class A volumetric flask. The stock solution was sonicated for 5 minutes to ensure dissolution. Standards used for the calibration curve were prepared gravimetrically at room temperature (22.0 °C) in HPLC grade water from the 512.0 ppm psilocybin stock solution.