Newly Synthesized Dihydroxyphenyl–Nitroaryl Schiff Base Immobilized on Silica for Green UA-DMSPE of Toxic Metals in Marine Samples: Experimental Performance, DFT Insights, Molecular Docking, and In Silico Toxicological Evaluation

), good precision (RSD < 3.0%), and strong tolerance toward common matrix constituents. The method was successfully applied to seawater and mussel samples, demonstrating reliable performance with controlled matrix effects. Density functional theory (DFT) calculations provided insight into the electronic properties and coordination behavior of TSL1, indicating favorable and comparable affinity toward the investigated metal ions, in agreement with the experimental extraction results. Molecular docking studies provided complementary information on potential biological interaction profiles. In addition, in silico toxicity assessment suggested an acceptable preliminary safety profile for analytical applications, and green analytical metrics confirmed the environmental compatibility of the proposed approach. Overall, the developed TSL1-functionalized silica sorbent combined with UA-DMSPE offers an efficient, selective, and environmentally benign strategy for trace-level determination of toxic metals in complex marine and food-related matrices.