Bimetallic metal-organic framework based dispersive solid phase extraction followed by using a carbon dot solution as the elution solvent; application in the extraction of imidacloprid and acetamiprid from pepper samples.

This study focuses on the dispersive solid phase extraction technique for the efficient extraction and enrichment of imidacloprid and acetamiprid from pepper samples. A synthesized sorbent was used for this purpose. Once the target analytes were adsorbed, the sorbent was separated using a centrifuge and the analytes were desorbed using a carbon dot solution. After centrifugation, a portion of the eluent was injected into a high-performance liquid chromatography-tandem mass spectrometry system for analysis of the analytes. Several parameters affecting the performance of the method were investigated, such as the amount of sorbent, the type and volume of elution solvent, pH, and so on. By optimizing these parameters, the method showed favorable results under the following conditions: a sample solution volume of 5 mL, a sorbent amount of 10 mg, vortexing for 2 min, 150 μL of carbon dot solution as the elution solvent, a pH of 10, and 3 min of agitation during the desorption step. Notably, this optimized method exhibited high extraction recoveries ranging from 67% to 78% as well as low detection limits (0.44 μg L^-1 and 0.32 μg L^-1) and quantification limits (1.4 μg L^-1 and 1.0 μg L^-1) for imidacloprid and acetamiprid, respectively. To validate the effectiveness of the method, four pepper samples were successfully analyzed and no analyte was detected in any of them using this approach. Overall, the developed DSPE method represents a reliable and sensitive technique for the extraction and analysis of the studied pesticides in pepper samples.