bionanocomposites based on halloysite nanotubes-zein and evaluation of their performance for thin film microextraction

In this work, a biocompatible sorbent based on halloysite nanotubes-zein bionanocomposite for direct-immersion thin film microextraction (di-tfme) is introduced. zein as a biodegradable, low cost and accessible polymer was used to prepare a flexible thin film with the possession of different interactions and good adsorption capacity. to enhance the mechanical and chemical stability of the film, halloysite nanotubes were added to the zein. the film was used for tfme of 16 pesticides from different chemical classes, including organochlorines and organophosphates followed by gas chromatography with electron capture detector (gc-ecd). to achieve the maximum efficiency and sensitivity, effective parameters such as the amount of halloysite nanotubes in bionanocomposite, type and volume of desorption solvent and desorption and extraction times were investigated and optimized. the linear dynamic range of the method was in the range of 0.1-300 μg l−1. the limits of detection and limits of quantification of the method were in the range of 0.01-0.04 μg l−1 and 0.03-0.12 μg l−1, respectively. the relative standard deviations for three replicates at the concentration levels of 5 and 50 µg l-1 were in the range of 3–12%. the method was validated for the tfme of pesticide residues in honey samples and recoveries for the spiked samples at two concentration levels of 5 and 50 µg l-1 were found to be in the range of 79-118%. the analytical results of the present method were comparable with some relevant methods currently used for the determination of pesticide residues. besides, the prepared sorbent was environmentally friendly, easy to prepare, and inexpensive.