A method and its application to determine the amount of cannabinoids in sewage sludge and biosolids

Stability of new psychoactive substances in crude wastewater

Those involved in drug testing continue to grapple with the dynamic nature of emerging psychoactive substances (NPS) and their rapid infiltration into society. The challenge extends beyond merely detecting and measuring NPS using analytical tools; it also encompasses the complexities arising from the formation and presence of metabolites and degradation products. This study utilises liquid chromatography time-of-flight mass spectrometry to investigate the stability of new psychoactive substances in wastewater. Seven NPS compounds including 25C-NBOMe, 5F-APINACA 4-hydroxyphenyl, AB-PINACA, APINACA 4-hydroxyphenyl, fentanyl, norfentanyl and MDPV, along with their corresponding internal standard, were examined. Reference material for each NPS compound was introduced into a wastewater sample from a Wessex water treatment plant. The sample was then exposed to four different environments: room temperature, refrigerator temperature, acidification to pH 2, and the introduction of sodium metabisulfite. The findings highlight the critical dependence of storage conditions on target analytes, emphasizing the paramount importance of the time elapsed between collection and analysis for NPS wastewater analysis. Notably, synthetic cannabinoids exhibit limited stability in wastewater whereas cathinone-like substances demonstrate greater stability. Furthermore, metabolites prove to be more stable in wastewater than the parent drug, suggesting that focusing on metabolite detection may be more favourable for future analysis.

Analysis of multi-class unregulated organic compounds in soil and biosolids using LC-MS/MS

Numerous unregulated organic compounds (UOCs) including pharmaceuticals, opioids, and personal care products (PCPs) end up in wastewater. UOC presence in biosolids (a wastewater treatment byproduct), which are applied to soil for different reasons raises environmental and health risk concerns. In this study, two multi-class extraction methods were developed and validated to target 111 UOCs from 8 different major families simultaneously in biosolids and biosolids-impacted soil. One method (M-SPE) is a modified version of EPA 1694, that uses triple solid-liquid extraction and solid phase extraction (SPE). The second method (EMR) is a super-fast method consisting in a single solvent extraction and EMR (enhanced matrix removal)-Lipid dispersive SPE. M-SPE performed better overall with 72 and 54 UOCs extracted with 50-130% recovery for soil and biosolids, respectively, compared to EMR for which only 49 and 43 UOCs achieved within the same range, respectively. EMR performed particularly well for the extraction of low concentration opioids from biosolids. The use of ENVI-Carb as an additional cleanup step and its potential to sorb analytes was also evaluated. Although >75% sorption of 27 UOCs occurred, ENVI-Carb (graphitized carbon) was needed to sufficiently clean extracts prior to injection to avoid precipitation and protect analytical systems. Application of these methods to environmental samples resulted in detection of some flame retardants, opioids, pharmaceuticals, PCPs and phthalates totaling 30 and 26 UOCs in biosolids and soil historically applied with biosolids, respectively. This methodology will be an asset to determining UOC concentrations in biosolids and biosolids-impacted soils.

Efficient removal of lipophilic compounds from sewage sludge: Comparative evaluation of solvent extraction techniques

Municipal sewage sludge, a by-product of wastewater treatment plants, presents environmental challenges due to its complex composition. Particular concern is the lipophilic and aliphatic compounds that pose risks to the environment and human health. This study focuses on the efficient removal of those compounds from sewage sludge using several organic solvents (hexane, toluene, chloroform, dichloromethane, acetone, hexane-methanol mixture, ethanol, and methanol) and ionic liquids (ILs) like tetrakis(hydroxymethyl)phosphonium chloride and 1-ethyl-3-methylimidazolium acetate by solvent extraction techniques. To determine optimal conditions, various factors such as solvent types, contact time, and temperature were examined. The results reveal that solvent polarity significantly impacts extract composition, with non-polar solvents like hexane and toluene yielding profiles characteristic of lipid-type compounds. An in-depth analysis of contaminants present in the sewage sludge was studied by Fourier-transform infrared spectroscopy (FTIR). Additionally, nuclear magnetic resonance (NMR) was used to identify the extracted compounds, including triglycerides, aliphatic esters, aliphatic alcohols, and free carboxylic acids. NMR provides data on the composition of the sewage sludge and indicates that among all the solvents used, tetrakis(hydroxymethyl) phosphonium chloride was the most suitable solvent for removing lipophilic and aliphatic compounds. Regeneration potential and reusability of the IL were conducted and verified by NMR. The results showed that tetrakis(hydroxymethyl) phosphonium chloride ionic liquid could be used for several extraction cycles. Identifying these compounds in the extracted mixture demonstrates that it adds value and potential for various applications. Towards environmental sustainability and circular economy, this effort develops strategies for the safe management, disposal, and recyclability of sewage sludge and, the reduction in environmental and health hazards associated with organic compounds.

A simple aptamer-dye fluorescence sensor for detecting Δ9-tetrahydrocannabinol and its metabolite in urban sewage

This work developed an aptamer-dye complex as a label-free ratiometric fluorescence sensor for rapid analysis of THC and its metabolite in sewage samples. Integrated with a portable fluorescence capture device, this sensor exhibited excellent sensitivity with visualization of as low as 0.6 μM THC via naked-eye observation, and THC analysis can be accomplished within 4 min, which would be a complementary tool for quantifying THC in sewage samples to estimate cannabis consumption.

Fluorinated-Squaramide Covalent Organic Frameworks for High-Performance and Interference-Free Extraction of Synthetic Cannabinoids

Synthetic cannabinoids (SCs), one of the largest groups of new psychoactive substances (NPSs), have emerged as a significant public health threat in different regions worldwide. Analyzing SCs in water samples is critical to estimate their consumption and control. However, due to their low background concentration and the coexistence of complex matrix, the selective and effective enrichment of SCs is still challenging. In this study, a series of fluorinated-squaramide-based covalent organic frameworks (COF: FSQ-2, FSQ-3, and FSQ-4) are synthesized, and the as-prepared FSQ-4 exhibits strong affinity to different SCs. The proper pore size (1.4 nm) and pre-located functional groups (hydrogen-bond donors, hydrogen-bond acceptors, and fluorophilic segments) work synergistically for efficient SCs capture. Remarkably, when coupled FSQ-4 with solid-phase microextraction (SPME), trace-level (part per trillion, 10-9 ) determination of 13 SCs can be easily achieved, representing one of the best results among NPS analyses, and the excellent extraction performance can be maintained under various interfering conditions.

Passive Sampler Technology for Viral Detection in Wastewater-Based Surveillance: Current State and Nanomaterial Opportunities

Although wastewater-based surveillance (WBS) is an efficient community-wide surveillance tool, its implementation for pathogen surveillance remains limited by ineffective sample treatment procedures, as the complex composition of wastewater often interferes with biomarker recovery. Moreover, current sampling protocols based on grab samples are susceptible to fluctuant biomarker concentrations and may increase operative costs, often rendering such systems inaccessible to communities in low-to-middle-income countries (LMICs). As a response, passive samplers have emerged as a way to make wastewater sampling more efficient and obtain more reliable, consistent data. Therefore, this study aims to review recent developments in passive sampling technologies to provide researchers with the tools to develop novel passive sampling strategies. Although promising advances in the development of nanostructured passive samplers have been reported, optimization remains a significant area of opportunity for researchers in the area, as methods for flexible, robust adsorption and recovery of viral genetic materials would greatly improve the efficacy of WBS systems while making them more accessible for communities worldwide.

Analysis of synthetic cannabinoids in wastewater of major cities in China

Synthetic cannabinoids (SCs) could pose serious health risks to its users. It is necessary to monitor its community consumption. Wastewater-based epidemiology is a potentially useful approach in this regard. However, limited research has been conducted to investigate the occurrence of SCs in wastewater. In this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was optimized to analyze 8 SCs and metabolites (in total 16 analytes) in wastewater. The limit of quantification for this method for certain analytes in wastewater was as low as 0.03 ng L^-1. The validated method was used to examine the stability of the analytes under different conditions and to examine their occurrence in wastewater collected from 31 major cities across China. The overwhelming majority of the analytes were stable within 24 h, even at room temperature. However, 5-fluoro MDMB-PICA and MDMB-4en-PINACA butanoic acid metabolite showed significant degradation within 120 days even when stored at -20 °C or -80 °C. At least one cannabinoid or their metabolite was detected in 21 cities. In the city with the highest detection rate, at least one synthetic cannabinoid or metabolite was detected in 95% of samples of the city. MDMB-4en-PINACA butanoic acid metabolite had the highest detection frequency (in 13.4% of the samples). These results indicated that SCs were used in a significant number of Chinese cities. A few parent drugs (MDMB-4en-PINACA, ADB-BUTINACA, 5-fluoro MDMB-PICA, 4-fluoro MDMB-BUTINACA) were detected in a small fraction of wastewater samples, possibly due to release from manufacturing of these cannabinoids or illegal addition of electronic cigarettes.

Developments in high-resolution mass spectrometric analyses of new psychoactive substances

The proliferation of new psychoactive substances (NPS) has necessitated the development and improvement of current practices for the detection and identification of known NPS and newly emerging derivatives. High-resolution mass spectrometry (HRMS) is quickly becoming the industry standard for these analyses due to its ability to be operated in data-independent acquisition (DIA) modes, allowing for the collection of large amounts of data and enabling retrospective data interrogation as new information becomes available. The increasing popularity of HRMS has also prompted the exploration of new ways to screen for NPS, including broad-spectrum wastewater analysis to identify usage trends in the community and metabolomic-based approaches to examine the effects of drugs of abuse on endogenous compounds. In this paper, the novel applications of HRMS techniques to the analysis of NPS is reviewed. In particular, the development of innovative data analysis and interpretation approaches is discussed, including the application of machine learning and molecular networking to toxicological analyses.