Preparation of a nano-biocomposite film based on halloysite-chitosan as the sorbent for thin film microextraction

This work introduced an environmentally friendly sorbent based on halloysite-chitosan nano-biocomposite for thin film microextraction (TFME). Chitosan as a biodegradable and biocompatible polymer was used to prepare thin film sorbent. To improve the mechanical and chemical resistance of the film and increasing the adsorption efficiency, halloysite nanotubes were combined with the chitosan to prepare the thin film sorbent. The film was used for TFME of 17 alpha-ethynylestradiol followed by high-performance liquid chromatography-fluorescence detection. Effective parameters such as the amount of chitosan and halloysite, ionic strength of sample solution, type and volume of desorption solvent, desorption and extraction times were optimized. The linear dynamic range of the method was in the range of 1.0-50.0 mu g L-1. The detection limit and relative standard deviation of the method were 0.4 mu g L-1 and 9%, respectively. The method was validated for the TFME of 17 alpha-ethynylestradiol in river water, wastewater, and tap water samples, and recoveries were found to be in the range of 67-106%.