Novel deep eutectic solvent-modified GO@MOF-808 for high-performance removal and detection of trace Entacapone and Tolcapone pollutants: Experimental and DFT Investigations

This study extends the development of a Graphene oxide@Zirconium-based metal-organic framework@Deep eutectic solvents (GO@MOF-808@DESs) through hydrothermal self-assembly using zirconium chloride and 1,3,5-benzenetricarboxylic acid (H 3 BTC), subsequently functionalized with four carbon-tailored fatty acid-based deep eutectic solvents (DESs) via ultrasonic impregnation. Comprehensive characterization of GO@MOF-808@DES confirmed the successful surface modification via DES. A dispersive micro-solid phase extraction(D-μSPE) method was established employing GO@MOF-808@DESs as an adsorbent for efficient removal of residual entacapone (ETCP) and tolcapone (TCP) from water. Optimization of the D-μSPE method revealed optimal conditions at pH 9.0, with a sample volume of 40 mL, an adsorbent dosage of 20 mg, and an adsorption time of 60 min. Under these conditions, the method achieved a significant adsorption capacity of 86.50 ± 4.79 mg/g for ETCP and 126.21 ± 2.72 mg/g for TCP. Mechanistic investigation revealed chemically dominated adsorption kinetics through pseudo-second-order modeling and Langmuir isotherm fitting. Concurrently, density functional theory (DFT) studies demonstrated that the synergistic effect between carboxyl-mediated hydrogen bonding and hydrophobic interactions led to enhanced adsorption performance. The engineered GO@MOF-808@DESs based D-μSPE method demonstrated superior performance in removing ETCP and TCP from river water matrices, achieving 99.67 % and 99.24 %, respectively. Meanwhile, a sensitive and reliable method for trace-level monitoring of ETCP and TCP residues in environmental waters was successfully proposed, employing GO@MOF-808@DESs-based D-μSPE coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). This study presents a robust strategy for fabricating high-performance GO@MOF-808@DESs composite materials, demonstrating significant potential for practical applications.