Electroanalysis最新文献

The quantification of tyramine (Tyr) and spermidine (Spd) is essential to protect and ensure quality and safety for food and beverage consumers. In this work, an electrochemical study was carried out, and a new, rapid, sensitive, reliable, and selective square-wave voltammetric method for simultaneously determining Tyr and Spd in wines was developed. A Chemically Modified Carbon Paste electrode with Zinc PhthaloCyanine (CMCPE-ZnPC) was used as a sensor in the electrochemical study, and a standard addition procedure (SAP) was employed to solve the matrix effect in the quantification of Tyr and Spd in wines. These analytes were electroactive on the stable, sensitive, and selective CMCPE-ZnPC sensor under study using SWV technique, displaying peak anodic potentials at around 400 mV for Tyr and 860 mV for Spd. Wine samples were analyzed using the proposed and reference methods. No statistically significant differences were observed among the results obtained for Tyr and Spd determinations, applying the paired t-test at a confidence level of 95 %. The proposed method yielded low limits of detection (6.8 nmol L⁻¹ for Tyr and 10.8 nmol L⁻¹ for Spd), good recovery rates (from 86.1 to 107.5 %), and reproducibility (overall RSD of 2.6 %). The proposed method contributes to green analytical chemistry since it uses no chemical pretreatment of the wine samples.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.

In the present study, a glassy carbon electrode (GCE) modified with Pd nanoparticles deposited on poly(acrylamide) gel brush-grafted magnetic particles (Pd/PAAm_GB@Fe₃O₄) with core-shell structure was fabricated for simultaneous electrochemical detection of dopamine (DA) and paracetamol (PA). Electrochemical performance of Pd/PAAm_GB@Fe₃O₄/GCE was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The fabricated sensor exhibited voltammetric sensing with a satisfactory linear determination range from 0.4–41 μM for DA and from 0.5–95 μM for PA. The limit of detection (LOD) was 0.1 μM for DA and 0.17 μM for PA based on signal to noise ratio of 3. The proposed sensor also had excellent reusability and selectivity, good reproducibility and stability, and satisfactory recovery in biomedical examples. It is believed that metal nanoparticles deposited on polymer gel brush composites may offer promising new horizons for sensor growth.

Using voltammetry to readout potentiometrically the solution acidity requires easy pH tunability of the probe's redox properties. In this work, tri-hydroxyphenyl porphyrin (POH₃) was synthesized as the electrochemically active probe to develop a voltammetrically potentiometric sensor (VPS) with a pH-sensitive response. By comparing POH₃ with control di- and mono-hydroxyphenyl porphyrins (POH₂ and POH₁), we found that protonation of the pyrrole macrocycle, electron communication of the para-hydroxyl groups with the pyrrole nitrogens during structure tautomerization, and the presence of multiple ionizable hydroxyl groups are the critical factors to report reversibly the pH-sensitive VPS response at the appropriate potential range. Common metal ions have negligible effects on the sensor performance. In comparison to the conventional potentiometric sensor (CPS), our VPS strategy benefits from the advantage that the electrode modification is not required. Thus, the complex phase boundary models necessary for CPS are unnecessarily involved in explaining the potential response.