Magnetic solid-phase extraction based on Ni-Zn ferrite/ Mg–Al (NO3) layered double hydroxide magnetite nanocomposite for determination of salicylic acid in real samples by differential pulse voltammetry

In the present study, magnetic solid-phase extraction (MSPE) method in combination with differential pulse voltammetry (DPV) electrochemical detection was applied to determine salicylic acid. MSPE method using a Ni-Zn ferrite/Mg– Al (NO3) layered double hydroxide (LDH)- based magnetite nanocomposite was developed for the pre concentration of salicylic acid in aqueous solutions. The electrochemical technique was applied by using a glassy carbon electrode modified with carbon nanotubes (CNTs) for determination of salicylic acid. The synthesized Mg– Al (NO3) LDH/Ni-Zn-Fe2O4 nanocomposite was characterized via X-ray diffraction, scanning electron microscopy and EDS. For achieving the best conditions of the extraction process, various parameters affecting the extraction recovery such as solution pH, the amount of Mg– Al (NO3) LDH/Ni-Zn-Fe2O4 nanocomposite, extraction time, elution conditions, sample volume and interfering effect of ions were studied. Under the optimized experimental conditions, linear range of calibration graph after pre concentration was obtained in the ranges of 0.05-5.5 µM with correlation coefficient of 0.9959 and detection limit of 1.56 ×10-8 M. To evaluate the precision of the method, 5 replicate samples at the certain concentration level were analyzed and the relative standard deviation value of 0.286 was reported. precision of the method in the terms of intra-day and inter-day relative standard deviations were 0.286% and 0.539%, respectively. Also, to study the accuracy of the method, the analysis of salicylic acid-spiked samples was performed and the satisfactory recovery value (95.42%-106.80%) was obtained.