A novel electrochemical sensor based on conducting polymer and multi-walled carbon nanotubes was reported for the detection of nitrite ions (NO2−). The hybrid material poly 1,8-Diaminonaphthalene (poly 1,8-DAN)/functionalized multi-walled carbon nanotubes (f-MWCNT) was prepared by using a simple electrochemical approach which is based on the deposition of functionalized multi-walled carbon nanotubes (f-MWCNT) on the surface of the electrode followed by the electropolymerization of 1,8-DAN using cyclic voltammetry. The morphology and the electro-catalytic properties of the obtained electrodes were investigated with Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) showing an improvement of the electronic transfer due to the synergic effect between the proprieties of poly 1,8-DAN and f-MWCNT. Under the optimum experimental conditions, the poly 1,8-DAN/f-MWCNT/CPE exhibited excellent electro-catalytic activity towards nitrite detection. The nitrite anodic peak potential decreased by 210 mV compared to the bare carbon paste electrode. The calibration plot of nitrite detection was linear in the range of concentration from 300 to 6500 nM with a low detection limit of 75 nM.

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Well‐known as a hazardous compound, nitrite constitute a real threat to the public health. So, there is a pressing need to detect and quantify them in different matrix. Even though conventional analytical methods can be used to address this issue, electrochemistry allows a fast, sensitive, and efficient analysis. Conducting polymers continue to raise great interest among scientific communities due to their properties. Moreover, their combination with carbon nanomaterials, or metallic nanoparticles improves their properties, and provides great results. In this paper, we will focus on some revealing works devoted to the electrochemical detection of nitrite using this kind of materials.

Bisphenol A (BPA) widely recognized as an endocrine disruptor can induce serious threats to human health such as sexual anomalies and cancer. Unfortunately, BPA has been increasingly used since 1950s; specifically during the manufacturing of polycarbonates and plastics such as food containers and water bottles. Thus, there is an urgent need to develop low‐cost, simple, portable and sensitive sensors for in‐situ detection of this contaminant in food and water. The combination of nanostructured carbon materials and metal/metal oxide nanoparticles can result in materials with unique physicochemical properties as well as excellent catalytic behaviors. Herein, we propose a smartphone‐assisted electrochemical sensor based on the combination of Mg0.5Co2.5(PO4)2 and carbon black (CB) modified screen‐printed electrode (SPE) for a rapid and sensitive determination of BPA. Structural characterization confirmed the formation of Mg0.5Co2.5(PO4)2/CB nanocomposite on SPE surface. Very low oxidation potential of BPA was observed during the differential pulse voltammetry (DPV) experiments at 0.16 V vs. Ag/AgCl. The sensor revealed two‐step linear response from 0.5–6.5 μm and from 16.5–100 μm with a lower limit of detection (LOD) of 0.15 μm. A good reproducibility, excellent stability, and high interference‐free ability were obtained. Furthermore, the developed sensor showed satisfactory recoveries for BPA detection in real water samples.