Flexible/self-supported zeolitic imidazolate framework-67 film as an adsorbent for thin-film microextraction

摘要

A flexible/self-supported zeolitic imidazolate framework-67 (ZIF-67) film was fabricated and applied as an adsorbent in the thin-film microextraction technique. This sorbent was synthesized by fabricating the electrospun cobalt oxide fibers, followed by phase transformation to the ZIF-67 fibrous film. The prepared film was used for the extraction of ethion (as an organophosphorus pesticide) prior to its determination by secondary electrospray ionization-ion mobility spectrometry. To obtain high extraction efficiency, some synthesis and extraction parameters (e.g., ionic strength, pH, stirring speed, and extraction time) were assessed and optimized. The linear dynamic range was obtained between 0.5 and 100 mu g L-1 with a detection limit of 0.1 mu g L-1. The relative standard deviations of intra-day and inter-day were less than 10% and 11%, respectively. Ethion was successfully determined in different real samples (underground water and agricultural wastewaters) by this method and the obtained recoveries were in the range of 91-107%, for spiked samples.