Sol-gel-based Chitosan/porphyrin-based covalent organic framework hollow fiber for enhancement of hollow fiber solid phase microextraction of acetamiprid and imidacloprid, followed by quantification through high-performance liquid chromatography.

In this study, a novel nanocomposite based on the combination of a porphyrin-based covalent organic framework (COF) and chitosan was synthesized and introduced for utilization in the hollow fiber solid phase microextraction method (HF-SPME). Herein, the prepared composite was accommodated in the pores of a porous polypropylene hollow fiber via the sol-gel method. The resulting HF-SPME device was employed to extract acetamiprid and imidacloprid (as the model analytes) from green beans samples (which were purchased from local markets in different areas of Sari, Mazandaran, Iran). The linear dynamic ranges (LDRs), limit of detections (LODs), and limit of quantifications (LOQs) were in the range of 0.50-500.00 μg l-1 (r2≥0.9983), 0.09-0.14 μg l-1, and 0.30-0.47 μg l-1, respectively. The enrichment factors of acetamiprid and imidacloprid were 114 and 135, respectively. Moreover, the absolute recoveries of the target analytes were 57.0 and 67.5%. The inter-day and intra-day relative standard deviations (RSD%) were calculated to be between 1.2-5.7%. The measurement of the target analytes in real samples showed spiking recoveries (SRs%) between 90.0-105.0% and the relative recoveries (RRs%) between 90.0-110.0% with an RSD% <4.4%. The results indicated that the proposed method offers high reproducibility, low detection limit, and good recovery for the extraction of selected analytes. Moreover, the performance of the sorbent and the greenness of the method were evaluated using the blue applicability grade index (BAGI) and the analytical greenness metric (AGREE) software, yielding scores of 70.0 and 0.84, respectively.