An optimal QuEChERS method for the determination of emerging contaminants by LC-MS/MS in the Antarctic bivalve Adamussium colbecki.

Emerging contaminants (ECs) are anthropogenic and naturally occurring chemicals detected in various environmental matrices, including remote regions such as Antarctica. Adamussium colbecki, an Antarctic bivalve, is an excellent bioindicator for assessing contamination in polar marine ecosystems. However, its high protein (10-18 %) and lipid (2-10 %) content require an effective sample pre-treatment to minimise matrix interferences during contaminant analysis. In this study, an optimised QuEChERS extraction method was developed and validated to determine ECs in A. colbecki using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). A multivariate experimental design approach was employed to improve analyte recovery (R%) and minimise matrix effect (ME%). Initially, a Plackett-Burman screening identified the most influential factors, which were subsequently optimised using a Doehlert design to construct quadratic models for response optimisation. The final method allowed to obtain acceptable recoveries (46-123 %) and satisfactory matrix effects (62-103 %) for 18 ECs, confirming its suitability for complex biological matrices. The optimised protocol was then applied to A. colbecki specimens collected during Antarctic campaigns in 2001, 2005, 2018, and 2019. Triclosan (TCS) was quantified in two samples and detected below the quantification limit in two others, while perfluorooctanoic acid (PFOA) and octyl-dimethyl p-aminobenzoic acid (OD-PABA) were identified at trace levels in 2005 samples. This study presents the first validated QuEChERS method for ECs analysis in A. colbecki, providing a reliable tool for long-term environmental monitoring and contamination assessment in the Antarctic marine ecosystem.