Facile hydrophobic modification of Cu-BTC for enhanced extraction and detection of trace phenolics in water

Copper 1,3,5-benzenetricarboxylate (Cu-BTC) holds promise for adsorption applications due to its high specific surface area, yet its aqueous instability severely restricts practical use. To overcome this limitation, a novel hydrophobic modification strategy using isopropyl alcohol (IPA) was developed to significantly enhance the structural stability of Cu-BTC in water. Capitalizing on this improved stability, the modified Cu-BTC-IPA was integrated with the conductive polymer 3,4-ethylenedioxythiophene (PEDOT) through electrodeposition copolymerization, creating a robust Cu-BTC-IPA@PEDOT composite coating for solid-phase microextraction (SPME). This developed coating enabled the establishment of a highly sensitive direct immersion SPME-GC-FID method for the efficient extraction and detection of six trace phenolic compounds. The resulting coating exhibited extraction capacities 2–8 times higher than the PEDOT and 6–40 times greater than the commercial PDMS coating. Adsorption mechanisms were elucidated through isotherm studies and electrostatic potential mapping. The established method exhibited low detection limits (0.01–0.08 μg L −1 ), a wide linear range (0.05–50 μg L −1 ), and was successfully applied to the analysis of five environmental water samples, yielding satisfactory recoveries ranging from 87.2 % to 117.9 %.