A new generation of solid-phase microextraction based on breathing of metal organic framework nanorods MOF-508 for the determination of diazinon and chlorpyrifos in wheat samples

Flexible MOFs with reversible transformations between open- and closed-pore forms are a new generation of materials that have been applied for gas separation, catalysis, and molecular sensing. This article introduces smart SPME (SSPME) as a new generation of SPME based on the breathing behavior of flexible MOFs with nanorod structures. Stainless-steel (SS) wires were coated with zinc (II)-based MOF, namely MOF-508, with benzene dicarboxylic acid and 4,4-bipyridine. The prepared SSPMEs were investigated to determine some pesticides in wheat samples. The results showed a low limit of detection (4 and 20 mu g Kg(-1)) and a wide linear dynamic range (20-4000 and 200-4000 mu g Kg(-1)) for the determination of diazinon and chlorpyrifos analytes using the SSPME-GC-FID method. The acceptable relative standard deviation for one-fiber, fiber-to-fiber, intraday, and interday modes was obtained 5.6-15%. The use of SSPME during the extraction process led to the minimum desorption time and complete desorption of pesticides analytes from the SSPME fiber.