Optimising QuEChERS for Mass Spectrometry Analysis: A Study of Trace Contaminants in Antarctic Biota

Emerging contaminants (ECs) are chemical species, both anthropogenic and naturally occurring, found in various environmental compartments [1]. Their spread can lead to known or suspected adverse effects on the ecosystem and human health, however, they remain largely unregulated [2]. The definition of ECs includes a wide range of categories, such as pesticides, pharmaceuticals and personal care products (PPCPs), illegal drugs, plasticisers, and hormones [3]. Even Antarctica, once considered a pristine environment, has not remained free from anthropic influences. Since the 1960s, synthetic organic compounds have been detected in Antarctic animal tissue [4]. These species can enter the Antarctic environment through long-range transport (LTR) or direct contamination from aeroplanes, boats, and even research stations [2]. The persistence of these contaminants in Antarctic ecosystems is intensified by the extreme environmental conditions, including low temperatures and prolonged darkness periods, which can significantly inhibit degradation processes [5]. The accumulation of ECs in polar biota poses a significant ecological risk, including mutagenicity, genotoxicity, and reproductive impairments in various species [6]. The simplicity of Antarctic trophic chains further amplifies the risks, as a small perturbance can cascade throughout the entire ecosystem. Bivalves, due to their filter-feeding behaviour are widely used as bioindicators of marine pollution [4,7]. The Antarctic scallop Adamussium colbecki is fitted for this role, being abundant in near-shore environments and endemic to the Southern Ocean [8]. However, the complexity of its biological matrix poses significant analytical challenges. The high concentrations of proteins (10-18%) and lipids (2-10%) of bivalves can interfere with the detection of ECs, necessitating an effective sample pretreatment strategy. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method, initially developed for pesticides analysis, offers a promising option due to its cost-effectiveness, efficiency, and broad-spectrum applicability [9]. This study presents a comprehensive optimisation of the QuEChERS method for the extraction of ECs from A. colbecki samples, followed by analysis via high-performance liquid chromatography coupled to tandem mass-spectrometry (HPLC-MS/MS). A multivariate experimental design was employed to optimise the extraction efficiency, evaluating the recovery (R%) and matrix effect (ME%) as key performance indicators. Initially, a Plackett-Burman screening design was applied to assess the influence of various independent variables including the solvent/ sample ratio, PSA and C18 amount, extraction and clean-up time, and centrifugation mode. The most statistically significant factors were further refined using a Doehlert response surface design to maximize extraction efficiency. The optimised protocol exhibited satisfactory recoveries (46-123%) and good matrix effects (62-103%) for 18 ECs, confirming its suitability for complex biological matrices. Following method’s performance evaluation, the QuEChERS procedure was applied to A. colbecki samples collected during Antarctic research campaigns in 2001, 2005, 2018, and 2019. Among the detected contaminants, triclosan (TCS), was detected in four samples, and quantified in two of them with concentration of 112 and 240 ng/g dry weight. Additionally, perfluorooctanoic acid (PFOA) and octyl-dimethyl p-aminobenzoic acid (OD-PABA) were detected in samples from 2005. Furthermore, suspect screening analysis (SSA) using high-resolution mass spectrometry (HR-MS) is currently being conducted to expand the scope of ECs identification in A. colbecki tissue. The integration of SSA with the optimised QuEChERS method enhances the ability to assess emerging pollutants in Antarctic biota in a more comprehensive way. This study represents the first validated application of QuEChERS extraction for ECs in the Antarctic organism A. colbecki, providing a reliable and standardised approach for long-term environmental monitoring. The optimised protocol offers a robust and efficient tool for detecting trace levels of contamination, contributing to a better understanding of the impact of ECs on the unique Antarctic marine ecosystem. Literature: [1] Khan S, Environ. Res. 2022, 207, 112609. [2] Lowther N, Univ. Canterbury Thesis Arch. 2014, 1-16. [3] Suavé S, Chem. Cent. J. 2014, 8:15, 1-7.[4] Mwangi JK, Environ. Pollut. 2016, 216, 924-934. [5] Olalla A, Sci. Total Environ. 2020, 742, 140417. [6] Postigo C, J. Hazard. Mater. 2023, 453, 131394. [7] Pizzini S, 2015, 121, 184-191. [8] Magi E, Appl. Organomet. Chem. 2004, 18:646-652. [9] Diallo T, Food Chem. 2022, 386, 132871.