A Simple and Highly Sensitive Electrochemically Reduced p‐Nitrobenzoic Acid Film Modified Sensor for Determination of Mercury

Abstract

Pulse techniques in electron paramagnetic resonance (EPR) allow for a reduction in measurement times and increase in sensitivity but require the synthesis of paramagnetic probes with long relaxation times. Here it is shown that the recently synthesized phosphonated trityl radical possesses long relaxation times that are sensitive to probe the microenvironment, such as oxygenation and acidity of an aqueous solution. In principle, application of Fourier transform EPR (FT‐EPR) spectroscopy makes it possible to acquire the entire EPR spectrum of the trityl probe and assess these microenvironmental parameters within a few microseconds. The performed analysis of the FT‐EPR spectra takes into consideration oxygen‐, proton‐, buffer‐, and concentration‐induced contributions to the spectral shape, therefore enabling quantitative and discriminative assessment of pH, pO2, and concentrations of the probe and inorganic phosphate.

A novel electrochemical sensor for determination of uric acid in the presence of ascorbic acid and dopamine based on a carbon paste electrode modified with an electrochemically reduced para-nitrobenzoic acid/graphene oxide nanocomposite

“…After 10 min stirring at 25 °C, a cyclic voltammetry program was applied from 0.6 V to −1.0 V ( vs. Ag/AgCl) at a scan rate of 100 mV s −1 for 12 cycles. 32 The ER p -NBA/GO/CPE was washed with double distilled water.…”

“…The second cathodic peak D appeared at about 0.12 V, which was paired with anodic peak C. The main pathway of electrochemical reduction of para -nitrobenzoic acid is shown in Scheme S1 (ESI†). 32…”

“…31 For example, an electrochemical sensor was fabricated for the determination of picomolar levels of Hg 2+ ions using differential pulse anodic stripping voltammetry by using electrochemically reduced p -nitrobenzoic acid on a glassy carbon electrode. 32…”

“…31 For example, an electrochemical sensor was fabricated for the determination of picomolar levels of Hg 2+ ions using differential pulse anodic stripping voltammetry by using electrochemically reduced p-nitrobenzoic acid on a glassy carbon electrode. 32 In this work, we fabricated a relatively simple ERp-NBA/GO/ CPE nanocomposite using the potentiostatic method in which the graphene oxide was mixed with CPE. Then in situ electrochemical deposition of para-nitrobenzoic acid was performed.…”

Two-dimensional FeS nanoflakes: synthesis and application to electrochemical sensor for mercury(II) ions

“…Hg 2? ions have been implicated in a number of fatal diseases such as Minamata disease, pulmonary edema, cyanosis, and nephrotic syndrome (WookáPark et al 2014;Arulraj et al 2014;An et al 2013), while it has been used as chemical additive and energy source in industrial development for decades. Because of these environmental and health problems of Hg 2?…”