Electrochemical paraquat sensor based on lead oxide nanoparticles

Abstract

The PbO nanoparticles-based electrochemical sensor can be integrated into a smartphone for on-site field testing of paraquat with high sensitivity and selectivity.

Sensitive electrochemical sensor based on nickel/PDDA/reduced graphene oxide modified screen-printed carbon electrode for nitrite detection

“…S3(b), † suggesting that the redox reaction on the electrode surface was a diffusion-controlled process. The electrochemically active surface area (ECSA) of Ni/PDDA/rGO/SPCE was calculated using the Randles–Sevcik equation for a reversible process: 39 I p = (2.69 × 10 5 ) n 3/2 AD 1/2 υ 1/2 C 0 where I p is the anodic peak current, n is the number of electrons transferred in the redox event, A is the electrochemically active surface area (cm 2 ), D is the diffusion coefficient (7.6 × 10 −6 cm 2 s −1 for Fe(CN) 6 3−/4− ), C 0 is the bulk concentration of the analyte (mol cm −3 ), and υ is the scan rate (V s −1 ). Based on the slope of the plot of I p vs. υ 1/2 , the calculated ECSA was 9.07 × 10 −2 cm 2 for Ni/PDDA/rGO/SPCE.…”

“…9(d) , and that of the higher range was I pa (μA) = 0.01552 C (μM) + 0.52154 with R 2 = 0.9954. The sensitivity was calculated to be 0.453 μA μM −1 cm −2 for the lower concentration range and 0.171 μA μM −1 cm −2 for the higher concentration range based on eqn (9) : 39 where m is the slope of the calibration plot (μA μM −1 ), A is the active surface area of the working electrode (cm 2 ). The two linear ranges of nitrite detection on Ni/PDDA/rGO/SPCE could be explained by the rapid conversion of nitrite into nitrate on the electrode surface in the low concentration range.…”

Recent Progress in Electronic Noses for Fermented Foods and Beverages Applications

“…Numerous gas sensors, a so-called sensor array, are the heart and most important component of the olfactory receptor. Various sensing materials, such as conducting polymers [38,39], carbon-based nanomaterials [40][41][42], metal oxides [43][44][45][46] and nanocomposites [47,48], have been used to adsorb odor molecules based on both physisorption and chemisorption. When the odor molecules adsorb on the sensing material surface, they lead to charge transfers, volume expansion, ion exchange or interaction with ion species that can cause changes in the electrical conductivity/resistivity of the sensing materials.…”

Two-Dimensional Non-Carbon Materials-Based Electrochemical Printed Sensors: An Updated Review

“…Reproduced/Adapted from Ref. [ 89 ] with permission from The Royal Society of Chemistry. ( b ) Ink-mixing and printing technique.…”