Analysis of drugs of abuse by online SPE-LC high resolution mass spectrometry: Communal assessment of consumption

An online SPE-LC-HRMS method was developed to monitor the consumption of 18 drugs of abuse (DOAs) including amphetamines, opioids, cocainics, cannabinoids, lysergics, and their corresponding metabolites in a well characterized college campus setting via wastewater analysis. Filtered and diluted (10 ×) sewage water samples (5 mL inj.) were automatically pre-concentrated and analyzed in 15 min using a Thermo EQuan MAX online SPE system equipped with a HyperSep™ Retain PEP (20 × 2.1 mm × 12 μm) SPE column and a Hypersil Gold™ aQ (150 × 2.1 mm × 3 μm) analytical column. A Q Exactive™ Hybrid Quadrupole-Orbitrap HRMS was used in full scan mode (R = 140,000) for positive identification, and quantitation of target compounds. Method detection limits for all analytes ranged between 0.6 and 1.7 ng/L in sewage. A total of 14 DOAs were detected from two different locations (dorms and main college campus) within a one-year period. Most frequently detected drugs throughout the entire study were amphetamine (> 96%) and THC's metabolite 11-nor-9-carboxy-Δ-9-THC (> 100%) with maximum concentrations of 5956 and 2413 ng/L respectively. Daily doses per 1000 people were determined in order to assess consumption of THC, amphetamine, heroin and cocaine, in both dorms and main campus.