Extraction and determination of diclofenac in food based on sulfonic acid-functionalized covalent organic framework composites by HPLC

Diclofenac (DCF), as fifth veterinary drugs, is a popular non-steroidal anti-inflammatory drug, widely applied in pain relief and anti-inflammatory of humans and animals, and endanger human health and food safety. Developing the effective technology for the removal or trace detection of DCF is urgent. Therefore, rational design and preparing advanced and selective adsorbent is extremely significant. Herein, a novel sulfonic acid (Sa) functionalized covalent organic frameworks (Fe 3 O 4 @TpbDva-Sa) were designed and prepared to enrich and determine trace DCF in milks with the aid of high performance liquid chromatography (HPLC). Fe 3 O 4 @TpbDva-Sa adsorbent was well characterized. The parameters of magnetic solid phase extraction (MSPE), adsorption kinetic and isotherm were evaluated in detail. Furthermore, adsorption mechanism of Fe 3 O 4 @TpbDva-Sa for DCF was investigated. The developed Fe 3 O 4 @TpbDva-Sa-MSPE-HPLC method was validated and employed to detect trace DCF in food samples. The established method displayed low dosage (2 mg), good linearity (8 × 10 -4 -10 μg mL −1 ), low limit of detection (2.4 × 10 -4 μg L -1 ), large adsorption capacity (98.03 mg g −1 ), good reusability and satisfactory recoveries (87–98 %). This work reported the novel magnetci sulfonic acid-based covalent organic frameworks for MSPE of DCF. The results revealed the great potency of Fe 3 O 4 @TpbDva-Sa for enriching the residues of veterinary drug in complex matrix and uncovered the prospects of functional covalent organic frameworks in sample pretreatment.