Showing papers on "Polarography published in 2023"
TL;DR: In this article , the authors report the first visualization of the interfacial turbulence developed at the polarized water/1,2-dichloroethane interface in the form of rotating surface structures.
TL;DR: In this article , a quantitative corrosion determination of carbon steel in hydrochloric acid by the use of polarographic and weight loss technique is presented. But the results are in good agreement with that of the polarographic measurements.
Abstract: The present work deals with the quantitative corrosion determination of carbon steel in hydrochloric acid by the use of polarographic and weight loss technique.
The polarographic peak obtained at (-0.27 v) in 0.1 M hydrochloric acid was used for the determination of iron and a calibration was ranged (10-5–10-3) M.
To confirm the obtained results a weight loss measurement were carried out, its results are in good agreement with that of the polarographic measurements. The research included in addition to that a kinetic study of corrosion reactions of iron in hydrochloric acid. Reaction rates were calculated at different temperature, and apparent energies of activation have been calculated from corrosion rates and Arrhenius plots.
10 Feb 2023
TL;DR: The question as to whether crude oil contains elemental or free sulfur has never been definitely settled, although there are many references in the literature to the presence of elemental sulfur in distillates and as condensed crystals in distillation equipment as mentioned in this paper .
Abstract: The question as to whether crude oil contains elemental or free sulfur has never been definitely settled, although there are many references in the literature to the presence of elemental sulfur in distillates and as condensed crystals in distillation equipment. There are also many references which indicate that a sulfur-bearing crude oil is very likely to evolve hydrogen sulfide during distillation. Inasmuch as distillation is one of the basic tools in separating the components of petroleum, it is helpful in knowing the sulfur content.
10 Feb 2023
TL;DR: In this article , the polargraphic characteristics of four alpha halogenated nitroparaffins were determined, i.e., 1-cholor-1-nitropropane, 2-chloro-2nitropropanes, 1-bromo-1.1.
Abstract: The purpose of this study was to determine some of the polargraphic characteristics of the reduction of four alpha halogenated nitroparaffins; 1-cholor-1-nitropropane, 2-chloro-2nitropropane, 1-bromo-1-nitropropane, and 2-bromo-2-nitropropane. An additional problem was the preparation and purification of the bromonitropropanes, since only the chloronitropropanes are available commercially.
TL;DR: In this article , a differential pulse polarographic (DPP) method was developed to measure low concentrations of hydrogen peroxide in Fenton and electro-Fenton processes in acidic solutions (∼3) and the presence of interfering species such as Fe3+ and dissolved oxygen.
Abstract: Knowing the concentration of hydrogen peroxide (H2O2) is crucial for the monitoring and optimizing the Fenton reaction in advanced oxidation processes. Several analytical methods exist to determine these concentrations, but their applications can be difficult because of low selectivity (interaction with other metals), the use of toxic compounds, or low concentrations (μmol LmmolL-1). To overcome these problems, we developed a differential pulse polarographic (DPP) method at the dropping mercury electrode (DME) with the following conditions: tg=1.0s, ΔE=−100mV and v=10mVs−1. Calibration curves had very high correlation coefficients (R2>0.999). The limits of detection and quantification were evaluated respectively at 13 and 21μmolL−1 with peak area measurements of hydrogen peroxide reduction (Ap). The DPP method was compared with other analytical methods (iodometric titration and spectrophotometry) for determining at low concentrations of H2O2 (in the order of mmolL−1 to μmol L−1) in Fenton and electro-Fenton processes. The method developed here allows measure low concentrations of hydrogen peroxide in Fenton and electro-Fenton processes in acidic solutions (∼3) and the presence of interfering species such as Fe3+ and dissolved oxygen.
08 May 2023
TL;DR: In this article , the results of kinetic measurements revealed an accelerating effect of acetazolamide (ACT) on the multistep In(III) ions electroreduction in chlorates(VII) on a novel, cyclically renewable liquid silver amalgam film electrode (R-AgLAFE).
Abstract: The results of kinetic measurements revealed an accelerating effect of acetazolamide (ACT) on the multistep In(III) ions electroreduction in chlorates(VII) on a novel, cyclically renewable liquid silver amalgam film electrode (R–AgLAFE). The kinetic and thermodynamic parameters were determined by applying the DC polarography, square-wave (SWV) and cyclic voltammetry (CV), as well as electrochemical impedance spectroscopy (EIS). It was shown that ACT catalyzed the electrode reaction (“cap-pair” effect) by adsorbing on the surface of the R–AgLAFE electrode. The catalytic activity of ACT was explained as related to its ability to form active In(III)- acetazolamide complexes on the electrode surface, facilitating the electron transfer process. The active complexes constitute a substrate in the electroreduction process and their different structures and properties are responsible for differences in the catalytic activity. The determined values of the activation energy ΔH≠ point to the catalytic activity of ACT in the In(III) ions electroreduction process in chlorates(VII). Analysis of the standard entropy values ΔS0 confirm changes in the dynamics of the electrode process.
[...]
TL;DR: AOAC Official Method 982.39Iodine in Thyroid Drug Tablets: Differential Pulse Polarographic Method First Action 1982 Final Action 1984 Apparatus Polarograph as mentioned in this paper .
Abstract: Extract AOAC Official Method 982.39Iodine in Thyroid Drug Tablets: Differential Pulse Polarographic Method First Action 1982 Final Action 1984 Apparatus Polarograph.—With dropping Hg electrode. Typical operating parameters: scan rate 5 mV/s; scan direction “−”; potential scan range 1.5 V; initial potential –0.9 V; modulation amplitude 50 mV; differential pulse operating mode; display direction “+”; drop time, 1 s; low pass filter off; push-button, initial; offset, off; current range 1–10 μ amp, or as needed. Reagents Use analytical reagents and glass-distilled H2O throughout. Correlation between tab let strength, iodine content, and standard solution 2 ... Add 1 mL Br2-saturated H2O and mix. Add Na2SO3 (ca 20 mg) until solution becomes colorless; mix. Dilute to volume with H2O and mix. Test Portion Preparation ... Determination Add ca 10 mL working solution to dry polarographic cell. Bubble N2 through cell 5 min; then direct stream of N2 above solution. Using typical operating parameters as guide, switch selector to external cell and wait until pen becomes stationary; then depress scan button. Similarly, using same settings, analyze test solution followed by reagent blank. From baseline established by reagent blank, measure peak heights of standard and test solutions at ca –1.18 V vs SCE. Calculate as follows:
[...]
TL;DR: The AOAC Official Method 968.16Fumaric acid in Food: Polarographic Method First Action 1968 Final Action 1969 Apparatus Polarograph as discussed by the authors , any voltammetric or polarographic instrument capable of effectively scanning up to 3.0 V in either positive or negative direction starting at selected initial potential.
Abstract: Extract AOAC Official Method 968.16Fumaric Acid in Food: Polarographic Method First Action 1968 Final Action 1969 Apparatus Polarograph.—Any voltammetric or polarographic instrument capable of effectively scanning up to 3.0 V in either positive or negative direction starting at selected initial potential. Reagents ... Preparation of Test Solutions ... Preparation of Standard Curve Transfer 1, 2, 3, 4, and 5 mL fumaric acid stock solution to separate 25 mL volumetric flasks. To flasks containing 1 and 3 mL stock solution, add 4 and 2 mL methanol, respectively. Dilute all flasks to volume with electrolyte solution. Polarograph solutions as in determination. Plot numerical values of signals against μg fumaric acid/mL. Determination Prepare polarograph cell and pass N2 through test solution B 3 min at ca 3–5 bubbles/s. Polarograph, using starting potential of −0.8 V. Peak potential of fumaric acid under these conditions is ca −1.15 V with Hg pool electrode. Wave height × instrument scale factor gives “numerical value,” which shows relative concentration of fumaric acid in polarographed solution. From numerical value of test solution B and standard curve, calculate approximate percent fumaric acid in test portion.
TL;DR: In this paper , the mutual interactions between polarography and pharmacology have been studied and the contribution of polarography to the quality control of pharmaceutical substances and dosage forms is discussed, including some interesting solutions to problems with the measurement of substances that are difficult to determine electrochemically.
Abstract: Abstract On the occasion of the centenary of the discovery of polarography, this article studies the mutual interactions between polarography and pharmacy. It highlights the relationship of the discoverer of polarography, Jaroslav Heyrovský (1890–1967), to pharmacy. The article shows how quickly and widely polarography has been applied to pharmacy. The contribution of polarography to the quality control of pharmaceutical substances and dosage forms is discussed, including some interesting solutions to problems with the measurement of substances that are difficult to determine electrochemically. The integration of polarography into pharmacopoeias is also followed. Next, the use of polarography in the determination of drugs and their metabolites in biological samples for pharmacological purposes is discussed. Finally, the application of polarography in the development of new drugs is reviewed. Although classical polarography on a dropping mercury electrode is nowadays seldom used, its contribution to pharmacy is considerable, and, moreover, new voltammetric methods derived from polarography still have a useful and irreplaceable position in pharmacy. Graphical abstract