Electrochemical deposition of silicate–cetyltrimethylammonium bromide nanocomposite film on glassy carbon electrode for sensing of methyl parathion

Zirconia nanocomposites with carbon and iron(iii) oxide for voltammetric detection of sub-nanomolar levels of methyl parathion

This study reports the synthesis of zirconia nanoparticles loaded on various carbon substrates, namely, reduced graphene oxide (Zr-r-GO), carbon nanotubes (Zr-CNT), and activated carbon (Zr-AC). In addition, a composite of zirconia-iron mixed oxide loaded on activated carbon (FeZr-AC) was also synthesized. The materials were characterized using SEM-EDX, HRTEM, FTIR, Raman spectroscopy, TGA and XRD. The FeZr-AC sample was found to have a nanorod like morphology. The samples were evaluated for their sensing potential towards methyl parathion (MP) using differential pulse voltammetry in a range of 0.0 V to -0.9 V (vs. Ag/AgCl) by drop casting on a glassy carbon electrode (GCE). All the modified GCEs best operated at a working potential of 0.4-0.9 V vs. Ag/AgCl/Cl-. FeZr-AC was found have the best limit of detection followed by Zr-AC, Zr-CNT and Zr-r-GO with their detection limits being 1.7 × 10-9 M, 17.2 ×10-9 M, 243.3 × 10-9 M and 534.0 × 10-9 M respectively. These materials were then used to detect MP in spiked sewage samples and showed good recoveries.

Nanostructured Diatom-ZrO2 composite as a selective and highly sensitive enzyme free electrochemical sensor for detection of methyl parathion

In the current work we report a simple and scalable technique for synthesis of ordered nanoporous Si-ZrO₂ composite derived from the diatom Phaeodactylum tricornutum. The composite was well characterized using SEM, TEM-EDX, FTIR, TGA, BET and DLS. The diatom-ZrO₂ was found to have a specific surface area of 140 m²/g, Si:Zr ratio of 1:4 and a particle size of 80 ± 2 nm. This composite was evaluated as an enzyme free electrochemical sensor towards the detection of methyl parathion (MP) and showed excellent sensing ability at extremely low detection limits of 54.3 pM and a linear concentration range of 3.4 nM to 64 μM. The diatom-ZrO₂ composite was also found to be highly selective towards MP as shown by its response even in the presence of high concentrations of other interfering molecules and ions.

Flame synthesis of nitrogen doped carbon for the oxygen reduction reaction and non-enzymatic methyl parathion sensor

We report nitrogen-doped carbon nanoparticles from a one-step flame synthesis by directly burning pyrrole at room temperature and in an air atmosphere.

A molecularly imprinted electrochemical enzymeless sensor based on functionalized gold nanoparticle decorated carbon nanotubes for methyl-parathion detection

Schematic of MP MIP sensor and the possible mechanism.

Differential pulse voltammetric determination of methyl parathion based on multiwalled carbon nanotubes-poly(acrylamide) nanocomposite film modified electrode

A sensitive electrochemical differential pulse voltammetry method was developed for detecting methyl parathion based on multiwalled carbon nanotubes-poly(acrylamide) (MWCNTs-PAAM) nanocomposite film modified glassy carbon electrode. The novel MWCNTs-PAAM nanocomposite, containing high content of amide groups, was synthesized by PAAM polymerizing at the vinyl group functionalized MWCNTs surface using free radical polymerization. The MWCNTs-PAAM nanocomposite was characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis and scanning electron microscopy. Electrochemical behavior and interference studies of MWCNTs-PAAM/GCE for methyl parathion were investigated. The experimental results demonstrated that the MWCNTs-PAAM/GCE exhibited a high adsorption and strong affinity toward methyl parathion compared with some metal ions and nitroaromatic compounds, which exist in environmental samples. The adsorbed amount of methyl parathion on the MWCNTs-PAAM/GCE approached the equilibrium value upon 5 min adsorption time. A linear calibration curve for methyl parathion was obtained in the concentration range from 5.0×10(-9) to 1.0×10(-5) mol L(-1), with a detection limit of 2.0×10(-9) mol L(-1). The MWCNTs-PAAM/GCE was proved to be a suitable sensing tool for the fast, sensitive and selective determination of methyl parathion in environmental water samples.