Detection of 3,4-diaminotoluene based on Sr0.3Pb0.7TiO3/CoFe2O4 core/shell nanocomposite via an electrochemical approach

Control of the sol-gel shell coating is important in the development of core-shell magnetic nanocomposites. Herein, we explored a scalable sol-gel method for the preparation of an Sr0.3Pb0.7TiO3/CoFe2O4 core-shell magnetic nanocomposite (SPT/CFO MNc) with a finely controlled shell and evaluated its efficiency as an electrochemical sensor. Firstly, CoFe2O4 nanoparticles were obtained via a citrate sol-gel method and sintered at 700 degrees C. Subsequently, Sr0.3Pb0.7TiO3 was applied to the CoFe2O4 nanoparticles to allow the formation of shells. The X-ray diffraction results indicated that the core nanoparticles have a cubic CoFe2O4 spinel structure and high-resolution transmission electron microscopy and scanning electron microscopy confirmed the successful formation of a uniform and thin Sr0.3Pb0.7TiO3 shell. The magnetic hysteresis loops confirmed the ferromagnetic nature of the as-prepared magnetic nanocomposite, which exhibited a saturation magnetization of 4 emu g(-1) and coercive field of 600 Oe. An electrochemical sensor selective toward 3,4-diaminotoluene was fabricated by coating the synthesized Sr0.3Pb0.7TiO3/CoFe2O4 core-shell magnetic nanocomposite onto a glassy carbon electrode. Detailed experimental analyses were performed to assess the analytical parameters of the proposed sensor. The calibration curve of 3,4-diaminotoluene was obtained by plotting the linear relation of current versus 3,4-DAT concentration. According to the slope of the calibration curve, the sensor sensitivity was calculated to be 24.3323 mu A mu M-1 cm(-2) by considering the surface area of the glassy carbon electrode (GCE: 0.0316 cm(2)). The linear dynamic range was estimated by considering the linear part of the calibration curve, which was found to be 0.1 nM-0.01 mM (linear dynamic range). Based on the signal-to-noise ratio of 3, the detection limit (96.09 +/- 4.80 pM) and limit of quantification (320.3 pM) were calculated. Furthermore, effective and satisfactory results were obtained in the analysis of environmental samples.