Determination of 21 synthetic cathinones, phenethylamines, amphetamines and opioids in influent wastewater using liquid chromatography coupled to tandem mass spectrometry.

Human consumption of illicit novel psychoactive substances (NPS) is a continuing problem. New derivatives are constantly appearing, circumventing national and international laws. The use of these compounds tend to be sporadic and many are consumed as mixtures, meaning very low amounts of each are detectable at any one time. The analysis of excreted NPS in wastewater provides information on community prevalence. A wastewater-based epidemiology approach has been applied in the current study for the quantification of 21 NPS. These include three phenethylamines (25B-NBOMe, 25C-NBOMe, 25I-NBOMe), ten synthetic cathinones (3-ethylmethcathinone (3-EMC), 3-methylbuphedrone, 3-methylmethcathinone (3-MMC), 4-fluoromethcathinone (4-FMC), 4-methylbuphedrone, 4-methylethcathinone (4-MEC), buphedrone, butylone, N-ethylpentylone and pentylone), five synthetic opioid analgesics (AH-7921, butyryl fentanyl, furanyl fentanyl, U-47700 and valeryl fentanyl) as well as the synthetic amphetamine 4-fluoroamphemtaine (4-FA), ketamine analogue methoxetamine and methiopropamine. Limits of detection were between 0.01 and 0.5 ng/L and limits of quantification were between 0.05 and 1 ng/L. The method was applied to wastewater samples from South Australia collected over the Christmas-New Year period when recreational drug use tends to be high. Seven NPS (butylone, butyryl fentanyl, furanyl fentanyl, methoxetamine, N-ethylpentylone, pentylone and valeryl fentanyl) were found, with N-ethylpentylone showing the highest mass loads at 36 mg/day/1000 inhabitants.