Covalent Organic Framework As Adsorbent for Ultrasound-Assisted Dispersive (micro)solid Phase Extraction of Polycyclic Synthetic Fragrances from Seawater Followed by Fluorescent Determination.

In this work, a new analytical approach based on ultrasound-assisted dispersive (micro)solid phase extraction (US-D-uSPE) using TpBD-Me-2 covalent organic framework (COF) as adsorbent for simple, rapid and selective fluorescent determination of two polycyclic synthetic fragrances in seawater, i.e., 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-(gamma)-2-benzopyran (HHCB), branded galaxolide (R), and 7-acetyl-1,1,3,4,4,6-hexamethyltetralin (AHTN), branded tonalide (R), is proposed. Different parameters involved in both adsorption and desorption steps were optimized in order to obtain the best results. High adsorption efficiencies in the range of 91.2-97.8% were achieved for both analytes. Desorption efficiencies of similar to 98% for AHTN and HHCB were obtained using methanol as solvent, rendering the material recyclable with merely minor losses in adsorption efficiency after five consecutive cycles of adsorption/desorption. Limits of detection (LODs) were 0.082 mu g L-1 and 0.070 mu g L-1 for AHTN and HHCB, respectively. The proposed method was successfully applied for the analysis of seawater without the need for a previous sample treatment, e.g., pH adjustment. Recoveries in the range of 90.4-101.2% with a relative standard deviation of 5.8% were obtained for both fragrances. The results proved the great capacity of TpBD-Me-2 COF for the selective sorption of polycyclic fragrances in combination with fluorescent detection, being highly promising for application to environmental monitoring of other emerging organic pollutants. (C) 2021 The Authors. Published by Elsevier B.V.