Nanoporous carbon fiber derived from Cu-BDC metal organic framework @pencil graphite as a sorbent for solid phase microextraction of acetamiprid and imidacloprid

Solid-phase microextraction (SPME) is a sample pretreatment technique for enrichment of trace level of compounds from complex matrices. The fiber coating, as an extraction phase, is the significant part of SPME, which specifying the analytical performance of the developed SPME. In this study, a novel in situ fabricated Cu@porous carbon fiber that derived from copper benzene-1,4-dicarboxylate framework@pencil graphite (Cu-BDC MOF@PG) fiber was prepared as a SPME fiber. The Cu-BDC MOF was electrodeposited on the surface of pencil graphite. The Cu@porous carbon fiber with nanoporous structure was constructed by the direct carbonization of the electrosynthesized fiber. The Cu@porous carbon fiber showed high analytical performance for direct immersion SPME (DI-SPME) of acetamiprid and imidacloprid in fruit and vegetable samples. The SPME method was coupled by high-performance liquid chromatography-ultraviolet detection (SPME-HPLC-UV) for determination of the analytes. Under the optimized condition, good linear ranges (1-500 μg L-1 and 0.5-200 μg L-1) and acceptable limits of detection (LODs = 0.30 and 0.15 μg L-1), appropriate spiking recoveries in the range 87-109.0% were attained for acetamiprid and imidacloprid, respectively. Intra- and inter-day relative standard deviations were found within the ranges of 2.35-3.46% and 3.30-3.70%, respectively. These results signify promising potential of the in situ fabricated porous carbon fiber for SPME applications. Considering that most of the pencil graphite is made of carbon, after the carbonization of the Cu-BDC MOF@PG fiber, a unified porous carbon fiber is obtained. Compared to other reported procedures, in situ direct carbonization of Cu-BDC MOF@PG fiber was a one-step and straightforward method to fabricate carbon fiber.