Abstract
Magnetic Co(0.8-x)ZrxNa0.2Fe2O4 nanocomposites (NCs) with controlled size were successfully synthesized by a facile low-temperature sol-gel method. The morphological and chemical properties of Co(0.8-x)ZrxNa0.2Fe2O4 NCs were controlled by (0.1-0.4) Zr content and particle size have been analyzed. The X-ray photoelectron spectroscopy (XPS) confirmed the chemical states for magnetic nanocomposites. Moderate saturation and coercivity (similar to 200-500 Oe) of the nanocomposites remark the plausible soft magnetic behavior with adjustable factors. Here, glassy carbon electrode (GCE) was covered by a thin film of the prepared Co(0.8-x)ZrxNa0.2Fe2O4 NCs, and 5% Nafion in ethanol was applied on the glassy carbon electrode (GCE) to obtain the desired 4-aminophenol (4-AP) sensor and was applied to electrochemical analysis in detail in the phosphate buffer (pH = 7.0). A plot of current versus concentration of 4-AP is found linear in the concentration of 0.1 nM similar to 0.01 mM labeled as the dynamic range (LDR) for the detection and the resulting plot is known as calibration curve. The slope of the calibration curve divided by a cross-section of GCE (0.0316 cm(2)) results in the sensitivity (10.5665 mu A mu M-1 cm(-2)) of the 4-AP sensor. Using the signal-to-noise ratio (S/N similar to 3), the lower limit of detection (98.45 +/- 4.92 pM) of the sensor is calculated. The 4-AP sensor exhibited substantial characteristics in terms of analytical parameters concluding response time, sensitivity, reproducibility, response time, and long-term stability in phosphate buffer. It is also evaluated in the detection of 4-AP with Co0.4Zr0.4Na0.2Fe2O4 NCs/GCE sensor in real environmental and extracted samples by applying the electrochemical approach. For environmental toxin monitoring, this noble approach might be potential in the development of future sensor technology with doped nanocomposite material by electrochemical approach on a broad scale.