Flame Retardants and Plasticizers in Aquatic Sediments: A Review of Extraction, Clean-Up and Instrumental Determination

Flame retardants (FRs) and plasticizers are widely used additives that can accumulate in aquatic sediments, where strong sorption and matrix complexity hinder reliable trace analysis. Because the available literature spans diverse compound classes, extraction strategies, clean-up procedures, and instrumental methods, a focused comparison is needed to clarify how analytical choices relate to method performance. Candidate studies published between 2015 and 2026 were identified primarily through Google Scholar, complemented by PubMed and publisher platforms. These studies were screened for relevance to FR and plasticizer determination in sediments. The resulting evidence base comprised 77 unique primary publications, yielding 80 category-specific analytical entries. The review is restricted to aquatic sediment matrices and focuses on sample pretreatment, extraction, clean-up/preconcentration, and instrumental determination, with occurrence, toxicology, and risk considered only where they provide analytical context. The literature is assessed across the main stages of the analytical workflow, i.e., sample pretreatment, extraction, clean-up, and instrumental analysis, with emphasis on recovery, detection limits, solvent use, extraction time, and procedural complexity. The reviewed evidence shows distinct extraction patterns between the two analyte classes: Soxhlet extraction and pressurized liquid extraction (PLE/ASE) are strongly represented among FR workflows, whereas ultrasound-assisted extraction predominates among plasticizer studies, with microwave-assisted extraction and other approaches employed to a lesser extent. The influence of solvent selection and clean-up requirements on compatibility with GC- and LC-based determination is also considered. Particular attention is given to the trade-offs between analytical performance and the environmental and operational cost of the complete pipeline, rather than assigning intrinsic greenness to individual extraction techniques. The reviewed studies reveal current methodological trends, recurring limitations in reporting and comparability, and priorities for more efficient, reproducible, and environmentally responsible monitoring of FRs and plasticizers in aquatic sediments.