A new sensitive layer based on clcinated Zn/Ti-MOF/magnetic molecularly imprinted polypyrrole: Application to preconcentration and electrochemical determination of perfluorooctane sulfonic acid by magnetic carbon paste electrode

In this research, a new approach based on magnetic electrodes has been developed for the determination of per-fluorooctane sulfonic acid (PSOF). Zinc and Titanium-based Metal-organic framework (MOF) was synthesized and used with polypyrrole as a conductive polymer for preparation of the absorbent to achieve the best performance for electrochemical application. The response of the electrode for determination of the PFOS was affected and optimized by different factors such as buffer solution, pH of the solution, amount of absorbent, extraction time of absorbent, accumulation time, as well as the Square Wave Voltammetry (SWV) instrumental parameters including voltage step, pulse amplitude, frequency and resting time. In the optimum condition, the response of the Zn/Ti/C-MOF-magnetic molecular imprinting polymer/carbon paste electrode (MOFMMIP/CPE) has increased logarithmically by increasing the concentration in the range of 0.002-165 μM by the limit of detection (LOD) of 0.7 nM. The obtained percentage of Recovery (96.00-104.14 %), Bias (-4.00 - 4.14 %) and Relative Standard Deviation (RSD) (1.89-3.74 %) for determination of the PFOS in real and spiked tap water, river water and well water samples demonstrates that the proposed method has an acceptable precision. The comparison between the gained data by the presented method and High-performance liquid chromatography (HPLC) showed that the presented method has high accuracy.