Win 55

The standards of synthetic cannabinoids JWH 018, JWH 073, AM 1220 and WIN 55 were purchased from Cayman Chemical (Ann Arbor, MI, USA) at a concentration of 1 or 0.1 mg mL -1 based on availability. Standards of cocaine (COC), phencyclidine (PCP), morphine (MOR) and methamphetamine (MAMP) were purchased from LGC Standard (Italy). The purity of the reference compounds was > 99%. All standards were provided at a concentration of 3 mM. Individual stock solutions were prepared in methanol at 300 μM and working standard mixtures were prepared by appropriate dilution of the standard solutions in methanol. All solutions were stored at -20 °C in dark condition. All buffer reagents, methanol, acetonitrile and water were acquired from Fisher Scientific (Fair Lawn, NJ, USA). All solvents employed in the extraction were ultra-performance liquid chromatography (UPLC) grade, and LC-MS grade.
The solid phase extraction sorbent materials VYWLVW-resin (W) and YYIGGF-resin (F), with a peptide substitution level of 0.17 mmol g -1 and a synthesis reproducibility > 95%. were bought from EspiKem srl (Italy). The resin used to attach the hexapeptides was a Fmoc-PAL-AM. The C-18 cartridges (30 mg mL -1 ) were from Phenomenex. SPE Isolute column (Empty 1 mL Reservoir) was from STEPBIO (Italy).