Development of a matrix solid phase dispersion methodology for the determination of triazine herbicides in marine sediments

A method based on Matrix Solid Phase Dispersion (MSPD) for the determination of nine triazines in marine sediments was optimized in terms of dispersant agents, co-sorbents and elution solvents. Three dispersing agents: octadecylsilyl bonded silica (C18), graphitized carbon black (GCB) and diatomaceous earth, and four clean-up co-sorbents: Florisil, GCB, primary and secondary amine (PSA)/strong anion exchanger (SAX), and GCB/PSA were assayed. The best results were obtained with GCB as dispersing agent, without co-sorbent, using 20 mL of ethyl acetate as elution solvent. Finally the extract was concentrated to dryness, re-constituted with 1 mL methanol and determined by HPLC-DAD. The analytical recoveries obtained were close to 100% and repeatability and reproducibility were below than 3.5% for all compounds. The linearity of the calibration curves was excellent in matrix matched standards, and yielded the coefficients of determination ≥ 0.9992 for all the target analytes. The LOQ values ranged from 0.022 to 0.037 mg kg− 1. Finally the method was applied to analyse the target compounds in marine sediment samples from the estuary of A Coruña (Galicia, NW of Spain).