Zirconium dioxide-reduced graphene oxide nanocomposite-coated stir-bar sorptive extraction coupled with ion mobility...

In this study, we developed zirconium dioxide-reduced graphene oxide nanocomposite (ZrO₂-rGO), as a novel coating for stir bar sorptive extraction (SBSE), prior to analysis by negative corona discharge ion mobility spectrometry (NCD-IMS). Ethion was selected as a test compound to evaluate the method. A stir bar was coated with the ZrO₂-rGO nanocomposite using the sol-gel technique. ZrO₂ has a high tendency towards the phosphonate group, hence its ability in absorbing ethion with high efficiency. On the other hand, graphene is a good sorbent for polar and semi-polar chemical compounds. Parameters affecting SBSE including extraction temperature, salt effect, stirring rate, desorption temperature, and extraction time were evaluated. The detection limit of this method for ethion was calculated to be 1.5 μg L^-1, and the good linear range of 5.0-200 μg L^-1 was obtained. The inter-day and intra-day relative standard deviations were 9% and 6%, respectively. This method was used to determine ethion in spiked river water and agricultural wastewater samples, and the obtained spiking recoveries were in the range of 93-97%.