Morphine

Carbinoxamine, chlorpheniramine, and chlorpheniramine-d₆ were purchased from TRC (North York, Canada). Individual solutions of 6-AM, 7-aminonitrazepam, 7-aminonimetazepam, amphetamine, benzoylecgonine, C6G, codeine, codeine-d₆, ketamine, methamphetamine, mephedrone, 4-methylephedrine, 3,4-methylenedioxymethamphetamine hydrochloride, M3G, M6G, morphine, morphine-d₆, and norketamine (each with a concentration of 1 mg mL⁻¹) were purchased from Cerilliant (Round Rock, TX, USA). Three brands of cold syrups (Consrine, ssBuron, and Pabron) manufactured in Taiwan were purchased from local pharmacies. Consrine contains codeine phosphate (0.48 mg mL⁻¹), chlorpheniramine (0.25 mg mL⁻¹), dl-methyl ephedrine HCl (1.6 mg mL⁻¹), and glycyrrhizic acid (0.25 mg mL⁻¹), ssBuron contains codeine phosphate (0.5 mg mL⁻¹), guaifenesin (3.33 mg mL⁻¹), chlorpheniramine maleate (0.14 mg mL⁻¹), and caffeine (1.33 mg mL⁻¹), Pabron contains codeine phosphate (0.48 mg mL⁻¹), dl-methyl ephedrine HCl (2.5 mg mL⁻¹), and carbinoxamine maleate (0.4 mg mL⁻¹). Formic acid and methanol (high-performance LC grade) (≥ 98%) were purchased from J.T. Baker (Pittsburgh, PA, USA). Ultrapure water (18.2 mΩ·cm) obtained from a Milli-Q ultrapure water system (Millipore, Billerica, MA, USA) was used in this study.

Morphine, oxycodone, hydrocodone, oxymorphone, hydromorphone, Δ⁹-tetrahydrocannabinol (THC) and its metabolites 11-nor-9-carboxy-tetrahydrocannabinol (THCCOOH) and THCCOOH-glucuronide were purchased from Cerilliant (Round Rock, TX, USA). The deuterated analogs THC-d₃, THCCOOH-d₃, THCCOOH-glucuronide-d₃, Morphine-d₃, oxycodone-d₆, hydrocodone-d₆, oxymorphone-d₃ and hydromorphone-d₆ were also purchased from Cerilliant. Strata XC 33 µm polymeric strong cation exchange cartridges of 3 mL/60 mg for calibrators and 6 mL/200 mg for quality control (QC) and authentic wastewater samples were purchased from Phenomenex (Torrance, CA, USA). Ultra-high performance liquid chromatography (UHPLC) grade methanol, dichloromethane and ammonium hydroxide were purchased from Pharmco-Aaper (Brookfield, CT). Isopropanol, liquid chromatography mass spectrometry grade acetonitrile, and Whatman glass microfiber filters (outside diameter 4.7 cm, particle retention 1.6 μm, and thickness 0.26 mm) were from Thermo Fisher Scientific (Waltham, MA, USA).