*WINNER* Analysis of wastewater samples for attention deficit hyperactivity disorder (ADHD) medications by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Abstract

Prescription rates for attention deficit hyperactivity disorder (ADHD) medications for both adults and children have been steadily increasing over the last two decades. Widely used ADHD medications include methylphenidate hydrochloride (Ritalin and Concerta), amphetamine (Adderall), and lisdexamfetamine dimesylate (Vyvanse). Urine excreted within 48-96 hours can contain 78-97% of the intact drug or metabolites. Because the drugs and their metabolites may not be removed from influent by conventional wastewater treatment, detectable concentrations can be found in wastewater effluent and in surface water, becoming an environmental problem. This research focuses on the detection of amphetamine, hippuric acid, methylphenidate, and ritalinic acid in wastewater. Influent and effluent wastewater samples were collected and filtered prior to solid phase extraction (SPE) using Oasis HLB cartridges. HLB is an all-purpose, strongly hydrophilic, reversed-phase, water-wettable polymer. Known concentrations of amphetamine-D5, methylphenidate-D9, and benzoylecgonine-D3 were added to all samples and to all calibration standards to serve as internal standards. Half of the collected samples were spiked with known concentrations of amphetamine, methylphenidate, and ritalinic acid, and the remaining half were not spiked. All samples were analyzed using a Varian ProStar210 high-performance liquid chromatograph system interfaced with a Varian 320 MS triple quadrupole mass spectrometer.