Cu-Al-LDH/porphyrin-based COF nanocomposite as a high-performance sorbent for hollow fiber solid phase microextraction of selected pesticide residues

The main objective of this study is to introduce a strategy for the synthesis of a new hybrid sorbent. This sorbent is based on the combination of layered double hydroxide (LDH) and a porphyrin-based covalent organic framework (COF), which is called (LDH/COF) for the hollow fiber solid-phase microextraction method (HF-SPME). For this purpose, Cu-Al-LDH was synthesized and combined with the tetra (4-aminophenyl) porphyrin to obtain a Cu-Al-LDH/porphyrin-based COF nanocomposite. Then, the synthesized composite was accommodated in the pores of the hollow fiber. The resulting extraction device was used to extract Hexaflumuron and Teflubenzuron (as the model analytes), present in food samples. The linear dynamic ranges, limit of detections, and limit of quantifications were in the range of 0.2–500.0 µg L−1 (r2 ≥ 0.9987), 0.08–0.19 µg L−1, and 0.27–0.63 µg L−1, respectively. The enrichment factors of Hexaflumuron and Teflubenzuron were 153 and 82, respectively. The relative standard deviations were calculated to be 1.7–4.3%. The environmental sustainability and practical applicability of the proposed method were evaluated using the Blue Applicability Grade Index (BAGI), which is a criterion based on a scoring scale of 0 to 100. The obtained score of 70.0 indicates good environmental compatibility and practical applicability of the method. The results showed that this sorbent provided high recovery, excellent reproducibility, and a low limit of detection for the extraction of target analytes.