Voltammetric determination of nitrite by using a glassy carbon electrode modified with a self-assembled nanocomposite prepared from CdTe quantum dots, cetyltrimethylammonium bromide, chitosan and multiwalled carbon nanotubes

A screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin for voltammetric sensing of nitrite

A disposable sensor is described for the determination of nitrite. A screen printed carbon electrode (SPCE) was modified with a 3D lamellar nanocomposite prepared by one-step electrodeposition from dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin. The modified SPCE exhibits high electrocatalytic activity toward nitrite oxidation, typically at a working potential at around 0.76 V (vs. Ag/AgCl). Sensitive and selective voltammetric detection of nitrite is demonstrated. The linear range extends from 1 to 2000 μM, the detection limit is 0.24 μM, and the sensitivity is 585.7 μA mM-1 cm-2. The method was applied to the determination of nitrite in (spiked) pickles. Graphical abstract Schematic presentation of fabrication of a screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin. Graphical abstract contains poor quality of text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.We have provided the original format of graphical abstract in the attachment.

A Facile Electrochemical Sensor Labeled by Ferrocenoyl Cysteine Conjugate for the Detection of Nitrite in Pickle Juice

Simple and facile electrochemical sensors for nitrite detection were fabricated by directly depositing ferrocenoyl cysteine conjugates Fc[CO-Cys(Trt)-OMe]₂ [Fc(Cys)₂] or Fc[CO-Glu-Cys-Gly-OH] [Fc-ECG] on screen-printed electrodes (SPEs). The modified carbon electrodes were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Results indicated that Fc-ECG/SPE sensor showed enhanced current response and a lower overpotential than Fc(Cys)₂/SPE sensor for nitrite detection. Optimal operating conditions were estimated for nitrite detection by DPV. The concentration of nitrite showed a good linear relationship with the current response in the range of 1.0–50 μmol·L⁻¹ and with 0.3 μmol·L⁻¹ as the concentration for limit of detection. There were no interferences from most common ions. The development of this electrochemical sensor was used for nitrite detection in pickled juice with a R.S.D. lower than 2.1% and average recovery lower than 101.5%, which indicated that disposable electrochemical sensor system can be applied for rapid and precise nitrite detection in foods.