Alprazolam

Standard solutions of the analytes alprazolam (ALP), citalopram (CIT), diazepam (DIAZ), doxepin (DOX), flunitrazepam (FLUN), fluoxetine (FLUOX), carbamazepine (CARB), cocaethylene (COCET), cocaine (COC), norcocaine (NORCOC), nordiazepam (NORDIAZ), nortriptyline (NORTR), oxazepam (OXA), temazepam (TEM), and venlafaxine (VEN) were purchased from Lipomed AG (Arlesheim, Switzerland). Deuterated derivatives of the analytes alprazolam-d5, diazepam-d5, flunitrazepam-d3, fluoxetine-d6, carbamazepine-d10, nordiazepam-d5, oxazepam-d5, and temazepam-d5, used as internal standards, were also purchased from Lipomed AG (Arlesheim, Switzerland). The selected number of 15 analytes, including six metabolites, was considered sufficient given that it was a preliminary study, and increasing the complexity of the method could potentially cause selectivity problems.
High-purity LC-MS chromatographic solvents acetonitrile, methanol, isopropyl alcohol, and sodium hydroxide obtained from Fluka Analytical (Seelze, Germany) were used in the experiment. Analytical-grade solvents acetonitrile, methanol, isopropyl alcohol, sodium hydroxide, and ammonium formate from Sigma-Aldrich (St. Louis, MO, USA) and formic acid obtained from Merck (Darmstadt, Germany) were also used. Deionized ultrapure water (18.2 M Ω · cm, TOC < 5 ppb) was obtained with the Milli-Q Plus system (Millipore, Bedford, MA, USA).

Methanol (MeOH) and acetonitrile (AcN), LC–MS grade, were purchased from HiPerSolv CHROMANORM^®. LC–MS grade isopropanol (IPA) was obtained from Fisher Scientific International, Inc., Hampton, NH, USA. A Milli-Q purification system (18.2 MΩ cm⁻¹) was used to provide ultrapure water. Ammonium formate (AF) ≥99% and formic acid (FA) 98–100% mobile phase additives were purchased from Riedel-de Haën^® (Sigma-Aldrich, Steinheim, Germany) and ChemLab, Zedelgem Belgium, respectively. Reference standards of diazepam, bromazepam, temazepam, oxazepam, alprazolam, 7-aminoflunitrazepam (7-AF), methadone, 3,4-methylenedioxymethamphetamine (MDMA), cathine, mescaline, cocaine, benzoylecgonine, methylecgonine, cocaethylene, 25B-NB2OMe, 25C-NB2OMe, 25I-NB2OMe, mephedrone, AH-7921, 1-Benzylpiperazine, methylone, 3,4-Methylenedioxypyrovalerone (MDPV), JWH-018, tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) were of more than 98% purity and were purchased from Lipomed AG (Arlesheim, Switzerland).
Dried blood spots (qDBSs) devices were obtained from Capitainer AB^® (Solna, Sweden).

Methanol solutions of fentanyl, methadone, EDDP, morphine, 6-monoacetylmorphine (6-MAM), cocaine, benzoilecgonine, and alprazolam and internal standard solutions of fentanyl-d5, methadone-d9, EDDP-d3, morphine-d3, 6-MAM-d3, cocaine-d3, benzoilecgonine-d3, and alprazolam-d4 (0.1 mg/mL), were purchased from Lipomed AG (Arlesheim, Switzerland). All solutions were stored in the refrigerator at +2–+4 °C when not in use. Mixed working standard solutions were prepared by combining the standards and aliquots of each primary solution and diluting them with Methanol. Methanol, dichlormethane, isopropanol, ammonium hydroxide, and others were purchased from Carlo Erba Reagents (Val-de-Reuil, France). Extraction Columns Clean Screen XCEL I and Selectra-SIL BSTFA w/1%TMCS were purchased from UCT (Bristol, PA, USA).