Thiol functionalized carbon ceramic electrode modified with multi-walled carbon nanotubes and gold nanoparticles for simultaneous determination of purine derivatives

Simultaneous Trace Electrochemical Determination of Xanthine Theophylline and Theobromine with a Novel Sensor Based on a Composite Including Metal Oxide Nanoparticle Multi‐walled Carbon Nanotube and Nano‐Na‐montmorillonite Clay

“…The slope values are close to the Nernstian slope of 0.059 V/pH for XT and TP that are consistent with the data in the literature, indicating that the oxidation mechanism of XT and TP on the electrochemical sensor involves an equal number of protons and electrons (two protons: two electrons) [45,46,47]. A slope of 0.019 V/pH for TB is approximately one-third of the Nernstian slope of 0.059 V/pH, which is consistent with literature data revealing that the electrooxidation mechanism is a twostep oxidation process involving 4 protons:4 electrons [8,14,47].…”

“…Despite their high accuracy and precision, spectroscopy and chromatography have some disadvantages to consider, such as the relatively costly equipment, the use of toxic organic compounds (solvents) that generate large quantities of waste. On the other hand, simultaneous detection using electrochemical sensors is emerging as a powerful and practical technique for quality-control tests and field analysis due to its high accuracy, selectivity, reproducibility, low cost, and easy operation characteristics [13,14].…”

Simultaneous Determination of Four DNA bases at Graphene Oxide/Multi-Walled Carbon Nanotube Nanocomposite-Modified Electrode

“…These interference studies are critical when developing a simultaneous sensor platform, because increasing the concentration of one analyte should not have a significant effect on the others. [46] These results demonstrated that there was no significant interference among the analytes and that simultaneous detection of all five analytes was possible using the nanocomposite-modified sensor. Furthermore, reproducibility of our sensor was investigated by evaluating peak current variation of measurements in 0.2 M PBS (pH 7.0) at 30, 57.5, 12.5, 147.5 and 97.5 µM of UA, G, A, T, and C, respectively.…”

“…where i c is the catalytic current, i L is the limiting current with no analyte, C h is the concentration of analyte in electrolyte, and t is time in s [46]. The K h values were determined as 1.45 × 10 3 M −1 s −1 , 3.31 × 10 4 M −1 s −1 , 7.24 × 10 4 M −1 s −1 , 1.39 × 10 2 M −1 s −1 and 1.11× 10 2 M −1 s −1 for UA, G, A, T, and C, respectively.…”

Electroanalysis based on stand-alone matrices and electrode-modifying films with silica sol-gel frameworks: a review

“…An example is an electrode made by adding nickel powder and graphite to methyltrimethoxysilane that was subsequently processed in a tube; it was applied to the oxidation of cystine, cysteine, and methionine [58]. Recently, an electrode was prepared from mercaptopropyl-methyldimethoxysilane, graphite powder, gold nanoparticles, and carbon nanotubes [59]; it was used for the differential pulse voltammetry of uric acid, xanthine, and caffeine. Detection limits in the range 50-100 nmol dm −3 were obtained.…”