A facile fabrication of electrodeposited metal organic frameworks thin film for headspace solid-phase microextraction of methamphetamine

Metal organic frameworks (MOF) have been considered appropriate coating materials for solid phase microextraction (SPME) fibers. This fact can be attributed to their special properties such as large surface area, good thermal stability and uniform structure.[1,2] Here, we report fabrication of a thin film of [Cu(btec)0.5DMF] (H4btec = 1,2,4,5-benzenetetracarboxylate acid) by a one-step in-situ cathodic electrodeposition.[3] Electrochemically synthesized MOF was formed on the surface of a stainless steel wire at a constant potential of -1.7 V at the presence of H4btec as the organic linker, copper nitrate and sodium nitrate. Surface investigation by scanning electron microscopy (SEM) revealed a highly porous structure. Also, electrosynthesized coating showed excellent thermal and mechanical stability. Parameters affecting the extraction efficiency such as pH, temperature, sample volume, ionic strength and extraction time were optimized to obtain the best recovery. The applicability of the fiber was investigated for analysis of methamphetamine in urine samples. The method provided good linearity over three orders of magnitude with quantification -limit (LOQ) of 0.2 ng mL-1, with an analytical recovery between 95% to 102 %. The relative standard deviation for three replicates at the concentration of 50 µg L-1 was found to be 5.6%.