Use of QuEChERS as a manual and automated high-throughput protocol for investigating environmental matrices.

Environmental pollution has strong links to adverse human health outcomes with risks of pollution through production, use, ineffective wastewater (WW) remediation, and/or leachate from landfill. 'Fit-for-purpose' monitoring approaches are critical for better pollution control and mitigation of harm, with current sample preparation methods for complex environmental matrices typically time-consuming and labour intensive, unsuitable for high-throughput screening. This study has shown that a modified 'Quick Easy Cheap Effective Rugged and Safe' (QuEChERS) sample preparation is a viable alternative for selected environmental matrices required for pollution monitoring (e.g. WW effluent, treated sludge cake and homogenised biota tissue). As a manual approach, reduced extraction times (hours to ∼20 min/sample) with largely reproducible (albeit lower) recoveries of a range of pharmaceuticals and biocidal surfactants have been reported. Its application has shown clear differentiation of matrices via chemometrics, and the measurement of pollutants of interest to the UK WW industry at concentrations significantly above suggested instrument detection limits (IDL) for sludge, indicating insufficient removal and/or bioaccumulation during WW treatment. Furthermore, new pollutant candidates of emerging concern were identified - these included detergents, polymers and pharmaceuticals, with quaternary ammonium compound (QAC) biocides observed at 2.3-70.4 mg/kg, and above levels associated with priority substances for environmental quality regulation (EQSD). Finally, the QuEChERS protocol was adapted to function as a fully automated workflow, further reducing the resource to complete both the preparation and analysis to <40 min. This operated with improved recovery for soil and biota (>62%), and when applied to a largely un-investigated clay matrix, acceptable recovery (88.0-131.1%) and precision (≤10.3% RSD) for the tested pharmaceuticals and biocides was maintained. Therefore, this preliminary study has shown the successful application of a high-throughput QuEChERS protocol across a range of environmental solids for potential deployment in a regulated laboratory.

QuEChERS: a simple extraction for monitoring quaternary ammonium biocide pollution in soils and antimicrobial resistance.

Quaternary ammonium compounds (QACs) are broad-spectrum disinfectants used in a range of everyday materials. Their high usage rates, limited regulation and reporting has meant their environmental release is largely uncontrolled and impact unknown. With links to antimicrobial resistance (AMR) and adsorption to wastewater solids (that are recycled), there is a need for more controlled disposal measures and monitoring. These environmental matrices are highly complex requiring methods that are often laborious and costly to undertake. Using a robust quantitative reversed-phase LC-MS/MS method, we have shown that an 'off the shelf' QuEChERS product can reliably extract (<10% RSD) aromatic and aliphatic QACs anticipated within municipal, industrial and agricultural waste from water and soil, with reduced matrix effects of 95.7-104.4% for recoveries of up to 53% from soil when combined with extract dilution. Therefore, unlike current literature, this work has shown that, with minimal development, the QuEChERS product can provide a rapid, effective and low cost preparation for quantifying QAC pollution and monitoring AMR.

An investigation of the utility of QuEChERS for extracting acid, base, neutral and amphiphilic species from example environmental and clinical matrices.

Accurate measurement of the composition of complex samples is key for the safety and efficacy of a range of products used in daily life, with sample preparation a critical step in this workflow. QuEChERS is one such method, however published protocols do not explicitly address acidic, basic, neutral, and amphiphilic species in a single protocol and often use extra steps or an alternative preparation to recover the breadth of chemical types. Our work addresses this need by investigating the use of QuEChERS for monitoring this wide range of chemistries within environmental solids and blood plasma, using a protocol that can accommodate both milliliter and microliter sample volumes. While published methods can require significant resource and time, our approach offers a reduction in preparation time (for environmental samples), with the "micro-QuEChERS" protocol offering a further reduction in cost. The analytical performance of these methods were assessed using reversed-phase LC-MS and showed good accuracy, precision, and sensitivity for the expected concentrations in the tested applications. Target analytes of variable lipophilicity/acidity were extracted and isolated from soil, with largely repeatable matrix effects < 15%RSD and recoveries of 39-100%. An initial "proof-of-concept" investigation using the "micro-QuEChERS" protocol showed reduced matrix enhancement (median value of 90%ME) for soil, and improved matrix effects and recovery (>65%) for blood plasma. This novel sample preparation method can therefore offer an improved approach with wider applicability providing "cleaner" extracts than other methods used for high-throughput clinical analysis.