In-situ Grown Covalent Organic Frameworks on Electrospun Nanofibers for Efficient Enrichment and Determination of Organophosphate Esters in Biodegradable Plastics.

In this work, a covalent organic framework (COF)-based nanofibrous composite (PAN@TFPB-TAPB) was fabricated through an in situ growth strategy and explored as a high-performance sorbent for thin film microextraction (TFME). Benefiting from the integration of electrospun polyacrylonitrile (PAN) nanofibers and TFPB-TAPB (2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde [TFPB] and 1,3,5-tris(4-aminophenylbenzene) [TAPB]), the composite mitigated the aggregation of conventional COF powders and provided accessible adsorption sites with good structural stability. The as-prepared PAN@TFPB-TAPB sorbent exhibited higher extraction efficiency toward seven organophosphate esters (OPEs) compared with pure PAN and TFPB-TAPB. On this basis, a sensitive and reliable TFME-gas chromatography-mass spectrometry method was established for the simultaneous enrichment and determination of OPEs in degradable plastic samples. Under the optimal conditions, the proposed method displayed wide linear ranges, low limits of detection, good precision, and satisfactory recoveries. Furthermore, this method was successfully applied to the analysis of OPEs in real complex plastic samples, demonstrating its great practical potential for the efficient monitoring of OPEs in environmental and commodity-related matrices.