As the dangers of cannabis abuse draw attention worldwide, it is necessary to assess the level of consumption in the community. The analysis of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) excreted in wastewater can provide information for a defined catchment area. Due to its hydrophobic nature and absence of ionizable groups, its detection is challenging. In this study, a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantitative determination of THC-COOH in urban wastewater. The derivatization reagent 6-methylpyridine-3-sulfonyl chloride (MPS) with analyte-specific fragmentation was proven to be the most effective for improving sensitivity. Samples were extracted by solid-phase extraction (SPE) and satisfactory recovery was achieved (>79%) by adding acetonitrile to the samples for ultrasonic-assisted extraction before filtration. The limit of detection (LOD) and limit of quantification (LOQ) was 0.03 ng L−1 and 0.1 ng L−1, respectively, from a 40 mL sample. The established methodology was applied to profile the presence of THC-COOH in influent wastewater samples. It was shown that 20 out of the 252 samples contained THC-COOH and the concentrations were all below 1 ng L−1.
Simin Chen,Yiqi Qie,Zhendong Hua,Haoyue Zhang,Youmei Wang,Bin Di,Mengxiang Su
Phytocannabinoids and their synthetic analogs (natural and synthetic cannabinoids) are illicit drugs that are widely abused worldwide. Wastewater-based epidemiology (WBE) is an objective approach for the estimation of population-level exposure to a wide range of substances, especially drugs of abuse. However, the concentrations of cannabinoids in wastewater are extremely low (frequently at the levels of nanograms per liter), and the existing pretreatment procedures for wastewater have the disadvantages of time-consumption or low extraction recoveries. This study aimed to propose a novel poly (methacrylic acid- co -ethylene glycol dimethacrylate)-functionalized polydopamine-coated Fe 3 O 4 nanoparticle (Fe 3 O 4 @ [email protected] (MAA- co -EGDMA)) as an adsorbent, and provide a highly sensitive quantitative analytical technique for the detection of five synthetic cannabinoids (SCs: 5 F-EDMB-PINACA, FUB-APINACA, MDMB-4en-PINACA, MDMB-FUBINACA, and PB-22) and one cannabis-related human metabolite (THC-COOH) in wastewater. The magnetic adsorbents were fully characterized by transmission electron microscopy (TEM), infrared spectroscopy (IR), vibrating sample magnetometry (VSM) and X-ray photoelectron spectroscopy (XPS). Subsequently, an MSPE-UHPLC-MS/MS method was developed and validated for the determination of six trace analytes in wastewater. The validation results showed that the method has limits of quantification as low as 0.1–1.0 ng/L. Additionally, the recoveries ranged from 62.81 to 124.02%, and the relative standard deviations (RSDs) of intraday and interday precision were less than 15%. This MSPE-UHPLC-MS/MS method was successfully applied to real wastewater samples, and the whole analytical process of one sample from pretreatment to the obtained quantitative results was completed in less than 30 min. Thus, the proposed method based on Fe 3 O 4 @ [email protected] (MAA- co -EGDMA) is a convenient, rapid, sensitive and reliable method for the determination of trace psychoactive drugs in wastewater.