Porphyrin-Based Covalent Organic Framework Reinforced Hollow Fiber for Solid-Phase Microextraction of Tebuconazole and Propiconazole.

Herein, an amino-functionalized covalent organic framework was synthesized and accommodated in the pores of porous hollow fiber. In this context, tetra (4-aminophenyl) porphyrin was synthesized for preparing the desired covalent organic framework as the extracting sorbent and employed for hollow fiber solid-phase microextraction of tebuconazole and propiconazole. With respect to the amino groups of the as-synthesized porphyrin-based covalent organic framework, the extracting device has the ability of establishing a hydrogen bond with the selected model analytes. Under the optimum condition, the linear range of the method for both analytes were estimated in the range of 0.5-200 µg L (the coefficient of determination of 0.9962 for tebuconazole and 0.9990 for propiconazole). The limits of detection of the method for tebuconazole and propiconazole were calculated to 0.02 µg g and 0.03 µg g, respectively. The limits of quantification of the method were also estimated for two analytes equal to 0.07 and 0.08 µg g, respectively. The intra- and inter-day relative standard deviations, which fell between 1.8% and 4.7%, were computed to assess the accuracy of the suggested approach. The proposed method was used for the extraction and determination of tebuconazole and propiconazole in tomato, cucumber, apple, cabbage, and carrot, which the obtained results showed the success of the method in extracting and determining of these analytes from the target samples.