Polarographic Method Research Articles

Effect of Maxima Suppressor and Supporting Electrolyte on Polarographic Wave of Dimethyl Sulfoxide and its Determination

The oxidation of the biologically very important dimethyl sulfoxide system has been the subject of investigations. In present study Dimethyl sulfoxide (DMSO) can be oxidized to dimethyl sulfone by anodic electrolysis at a rotating platinum electrode. The polarographic method has been used to study qualitatively the effect of maxima suppressor gelatin, fuchsin, methyl red, thymol blue and supporting electrolyte HCl, CH3COOH on oxidation wave of DMSO. Polarographic oxidation of DMSO in 0.1 M HCl, 0.1 M CH3COOH solution using optimum concentration of fuchsin, methyl red, thymol blue as surface active substances is followed to determine the DMSO present in synthetic sample by calibration method. Wave analysis indicate the irreversible nature of the oxidation process which involves oxidation of dimethyl sulfoxide to dimethyl sulfone thereby increasing the oxidation state of sulphur from +2 to +4 state.

Polarographic Study of Meta-Hydroxyacetanilide and its Determination

Present paper deals with polarographic study of effect of maxima suppressors and supporting electrolytes on anodic waves of meta-hydroxyacetanilide and polarographic determination of meta-hydroxyacetanilide under optimum concentration of maxima suppressors and supporting electrolytes. The polarographic method has been developed to study qualitatively the effect of maxima suppressor (fuchsin) and supporting electrolyte (nitric acid) on oxidation wave of meta-hydroxyacetanilide. Polarograms of system were recorded between 500 to 1300 mV by using Rotating Platinum micro Electrode as anode and Saturated Calomel Electrode as cathode on D.C. Recording Polarograph using Omniscribe recorder. It shows a similar behavior to that observed for paracetamol. It produces anodic wave at rotating platinum electrode. The oxidation yields the 3-N-acetylaminosemiquinone and represents a reversible reaction. Polarographically a value of 900 mV is found for decomposition potential of meta-hydroxyacetanilide. Wave analysis point to 1-electron step for each wave. Waves of meta-hydroxyacetanilide are only proportional to concentration at low concentrations.

Patterns of endothelium-dependent circulation reactions development in patients with ischemic stroke in case of oxigenation disturbances

Aim. To study features of tissue oxygenation and changes in nitroxidergic and endothelinergic mechanisms of circulation regulation in ischemic stroke and hypoxia modeling.
 Methods. 74 men and women with ischemic stroke were examined and experimental study on 30 outbred white male rats was conducted. All patients underwent computed tomography of the brain, neurological status was assessed and general clinical examination was performed. Tissue oxygen tension was measured percutaneuosly using polarographic method. Chronic hypoxic hypoxia was simulated in animals by daily 40-50 minutes inhalation of 10% oxygen mixture for 4 weeks. Blood oxygen tension was evaluated in patients and laboratory animals. Nitric oxide level of was assessed by determining its stable metabolites. Endothelin-1 level was determined by ELISA. Data was analyzed using «Statistica 8.0» software using non-parametric tests. Differences were considered as statistically significant at p

Polarographic and voltammetric determination of genotoxic 4-nitroindane at mercury electrodes

Determination and electrochemical investigation of genotoxic nitrated polycyclic aromatic hydrocarbon 4-nitroindane (4-NI) were carried out using direct current tast polarography (DCTP) and differential pulse polarography (DPP) at a classical dropping mercury electrode (DME) and using direct current voltammetry (DCV), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) at a hanging mercury drop minielectrode (HMDmE). The following optimal media for the determination of 4-NI were found: methanol—Britton-Robinson (BR) buffer of pH 12.0 (1:1) for DCTP and DPP, methanol—BR buffer of pH 9.0 (1:9) for DCV, and methanol—BR buffer of pH 8.0 (1:9) for DPV. For CV investigation, mixtures of methanol—BR buffer of pH 3.0, 8.0, and 12.0 (1:1) were used. The limits of quantification were: 0.65 µmol dm−3 (DCTP at the DME), 0.10 µmol dm−3 (DPP at the DME), 0.075 µmol dm−3 (DCV at the HMDmE), and 0.070 µmol dm−3 (DPV at the HMDmE). An attempt to increase the determination sensitivity using adsorptive accumulation of 4-NI on the HMDmE surface was not successful. The newly developed polarographic and voltammetric methods were successfully applied for the determination of 4-NI in model samples of drinking and river water.

Oxygen permeability of soft contact lenses in different pH, osmolality and buffering solution.

To determine the effect of pH, osmolality, and buffering system on the oxygen permeability (Dk) of soft contact lenses. Two hydrogel lenses (nelfilcon A and etafilcon A) and 2 silicone hydrogel lenses (lotrafilcon A and balafilcon A) were used in the study. These lenses were incubated in phosphate-buffered saline (PBS) and borate-buffered saline (BBS) solutions adjusted by 0.8 pH increments to a pH in the range of 5.8-9.0 or in hypotonic (280 mOsmol/kg), isotonic (310 mOsmol/kg) and hypertonic (380 mOsmol/kg) PBS solutions. Polarographic method was used for measuring the Dk and lenses were stacked as 4 layers to correct the boundary effect. Dk values of all contact lenses measured in BBS solutions were more stable than those in PBS solutions. Especially the etafilcon A lens showed a relative big change compared with other types of contact lenses at the same conditions. When the osmolality of PBS solution increased from hypotonic to hypertonic, Dk of all contact lenses decreased. Variations in Dk existed depending on lens materials, etafilcon A lens was the most affected and nelfilcon A was the least affected by osmolality. From the result obtained, it is revealed that Dk of contact lenses is changed by the pH, osmolality, and buffering condition of tear. Thus, Dk of contact lens can be varied by the lens wearers' physiological and/or pathological conditions.

THE CHARACTERISTIC OF ENERGY METABOLISM OF THE SMALL INTESTINE OF INTACT RATS

Objective: to study the indicators of tissue respiration and oxidative phosphorylation of the rings of the mucous membrane of the duodenum intact in white rats. Material and methods. We used white male rats with body mass of 180-230 g. The parameters of tissue respiration and oxidative phosphorylation were studied by the polarographic method on the device «Record 4». Results. The work gives the characteristic of the key parametres of tissue respiration and oxidative phosphorylation of the mucous membrane of the small intestine of intact white rats. It shows high respiratory activity both on endogenous, and exogenous substrates, which is caused by the fact that the small intestine perform a great number of energy-dependent metabolic functions. Conclusion. Saturated and unsaturated fatty acids make a great contribution to the energy properties of the small intestine. The intensity of tissue respiration and oxidative phosphorylation of the mucous membrane of the small intestine is consistent with other aerobic tissues.

Correction of mitochondrial dysfunction of rabbit cardiomyocytes using substrate antihypoxants

Features of energy metabolism in children with cardiovascular diseases are of great practical importance. It is prognostically important to determine the status of the energy of cardiomyocytes to normalize bioenergetic deficit cardiomyocytes in rheumatoid arthritis, myocarditis, congenital heart diseases to decrease reduction in myocardial contractility and reduce precondition for the progression of heart failure. The experimental and clinical studies of the pathogenesis of idiopathic cardiomyopathy in children in recent years indicate directly the damage of oxidative phosphorylation in myocardial tissue due to decreased activity of the mitochondrial electron transport system. Numerous congenital diseases like syndrome Ivemark, Holt-Oram, Ellis-Van Creveld, Ivemark, Noonan, Greeg, Kugel-Stoloff, Werner, West, Adams-Stokes, MERRF include cardiomyopathy in their symptoms. Vibration-type model of hypoxic cell metabolism was suggested to estimate antihypoxant succinic acid as cardioprotective substance in in drug “Amber-antitoks” on rabbit cardiomyocytes. The experiment of bioenergy dependent reaction of native heart mitochondria was studied by polarographic method performed using a closed membrane Clarke’ electrode. Pharmacological drug “Amber-antitoks” in dose as 8.4 mg/kg prevents the formation of bioenergy dependent hypoxia of cardiomyocytes and restore the activity of NAD-dependent, and suppress hyperactivity suktsinat-degidrogenaze enzyme-substrate complex of the respiratory chain. It causes reduction of the severity of mitochondrial dysfunction and the degree of morphological myocardial tissue damage. The protective properties of drug “Amber-antitoks” allow to recommend it for using in the treatment in combination with other drugs of cardiovascular disease in children.

Determination of Lipid Hydroperoxides in Marine Diatoms by the FOX2 Assay.

Ecologically-relevant marine diatoms produce a plethora of bioactive oxylipins deriving from fatty acid oxidation, including aldehydes, hydroxy-fatty acids, epoxy-hydroxy-fatty acids, and oxo-acids. These secondary metabolites have been related to the negative effect of diatoms on copepod reproduction, causing low hatching success and teratogenesis in the offspring during periods of intense diatom blooms. The common intermediates in the formation of oxylipins are fatty acid hydroperoxides. The quantitative measurement of these intermediates can fundamentally contribute to understanding the function and role of lipoxygenase metabolites in diatom-copepod interactions. Here, we describe the successful adaptation of the ferrous oxidation-xylenol orange 2 (FOX2) assay to diatom samples, which showed several advantages over other spectrophotometric and polarographic methods tested in the present work. Using this method we assessed fatty acid hydroperoxide levels in three diatom species: Skeletonema marinoi, Thalassiosira rotula, and Chaetoceros affinis, and discuss results in light of the literature data on their detrimental effects on copepod reproduction.

Capillary electrophoresis method for speciation of iron (II) and iron (III) in pharmaceuticals by dual precapillary complexation.

Pharmaceutical iron sucrose is an iron (III) replacement for the treatment of iron deficiency anemia in patients with chronic kidney disease. The drug product (injection) is a colloidal solution of ferric hydroxide in complex with sucrose, containing 20 mg/mL elemental iron; according to United States pharmacopoeia (USP), the limit of iron (II) is 0.4% w/v. A selective CE method for the simultaneous determination of iron (III) and its potential impurity iron (II), was developed by applying a dual precapillary complexation. In particular, 1,10-phenanthroline and 1,2-diaminocyclohexanetetraacetic acid were used for complexation of iron (II) and iron (III), respectively. Sample preparation was optimized to achieve mineralization of pharmaceuticals using HCl 6 M, by avoiding perturbation of the oxidation status of both iron species. Simple CZE conditions, involving a 60 mM (pH 9.3) tetraborate buffer at the constant voltage of 25 KV and 25°C, allowed fast separation of iron (II) and iron (III) complexes that were detected at 265 nm. Sensitivity for iron (II) determination was found to be 4.80 μM (LOQ) corresponding to 0.15% w/w with respect to the total iron test level. The method was validated by following International Conference on Harmonization guidelines for specificity, linearity, precision, accuracy, and robustness and it was applied to real pharmaceutical samples. The obtained results suggested that the method can be a useful alternative to the official USP and British pharmacopoeia polarographic method.

Linalool effect on mitochondrial bioenergetics rat liver

Antecedentes: El linalool (2,6-dimetil-2,7-octadien-6-ol) es un monoterpeno presente en mas de 200 tipos de plantas, y constituye el componente mayoritario de varios aceites esenciales. El linalool posee una amplia variedad de potenciales propiedades farmacologicas; que van desde propiedades antisepticas, ansioliticas, anti-inflamatorias, antifungicas, antimicrobianas y proapototicas en diferentes lineas de celulas tumorales. Sin embargo, su principal uso esta relacionado como una molecula odorante o fragancia en productos de uso topico en productos cosmeticos y en la industria del perfume. Objetivo: En este estudio se evaluo el efecto del linalool sobre la bioenergetica de mitocondrias aisladas de higado de rata. Metodos: El linalool en concentraciones entre (5-100μg/mL) fue evaluado en mitocondrias aisladas de ratas machos albinas raza Wistar, de acuerdo al metodo descrito por Voss et al (1961). Inicialmente, se determino el consumo de oxigeno en mitocondrias intactas mediante un metodo polarografico por medio de un oxigrafo. Posteriormente, se determino el efecto del compuesto sobre las enzimas de la cadena respiratoria mitocondrial usando metodos polarograficos y espectrofotometricos. Resultados: Los resultados obtenidos indican que el linalool en las concentraciones de 5, 10, 50 y 100μg/mL, afecta la velocidad de consumo de oxigeno en el estado 3 y 4 de mitocondrias energizadas con glutamato-malato y succinato. Sin embargo, el efecto inhibitorio es mayor al usar glutamato-malato como sustrato. Por su parte, el analisis de la actividad de las enzimas de la cadena respiratoria mitocondrial mostro que el linalool (50μg/mL) inhibe los complejos I, III y la actividad ATPasa. Conclusiones: El linalool inhibe el complejo I, complejo III y la ATPasa, esta inhibicion podria aumentar la generacion de especies reactivas de oxigeno.

Determination of Methyl Violet 2B using Polarographic and Voltammetric Methods at Mercury Electrodes

ABSTRACTDirect current tast polarography and differential pulse polarography at a dropping mercury electrode and direct current voltammetry, differential pulse voltammetry, and differential pulse adsorptive stripping voltammetry at a hanging mercury drop electrode were employed for the electrochemical characterization and determination of methyl violet 2B in buffered aqueous media and model water samples. The optimum medium for all techniques was 0.04 mole per liter Britton-Robinson buffer at pH 4.0. The limits of quantification for methyl violet 2B were 1.7 micromole per liter (direct current tast polarography at the dropping mercury electrode), 0.16 micromole per liter (differential pulse polarography at the dropping mercury electrode), 65 nanomoles per liter (direct current voltammetry at the hanging mercury drop electrode), and 45 nanomoles per liter (differential pulse voltammetry at the hanging mercury drop electrode). The lowest limit of quantification of 13 nanomoles per liter was obtained using differential pulse adsorptive stripping voltammetry at the hanging mercury drop electrode with an accumulation potential of −500 millivolts and an accumulation time of 600 seconds. The optimized conditions were employed for the determination in drinking (limit of quantification of 40 nanomoles per liter) and river (limit of quantification of 20 nanomoles per liter) water.

Sorafenib prevents liver fibrosis in a non-alcoholic steatohepatitis (NASH) rodent model.

Liver fibrosis occurring as an outcome of non-alcoholic steatohepatitis (NASH) can precede the development of cirrhosis. We investigated the effects of sorafenib in preventing liver fibrosis in a rodent model of NASH. Adult Sprague-Dawley rats were fed a choline-deficient high-fat diet and exposed to diethylnitrosamine for 6 weeks. The NASH group (n=10) received vehicle and the sorafenib group (n=10) received 2.5 mg·kg-1·day-1 by gavage. A control group (n=4) received only standard diet and vehicle. Following treatment, animals were sacrificed and liver tissue was collected for histologic examination, mRNA isolation, and analysis of mitochondrial function. Genes related to fibrosis (MMP9, TIMP1, TIMP2), oxidative stress (HSP60, HSP90, GST), and mitochondrial biogenesis (PGC1α) were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). Liver mitochondrial oxidation activity was measured by a polarographic method, and cytokines by enzyme-linked immunosorbent assay (ELISA). Sorafenib treatment restored mitochondrial function and reduced collagen deposition by nearly 63% compared to the NASH group. Sorafenib upregulated PGC1α and MMP9 and reduced TIMP1 and TIMP2 mRNA and IL-6 and IL-10 protein expression. There were no differences in HSP60, HSP90 and GST expression. Sorafenib modulated PGC1α expression, improved mitochondrial respiration and prevented collagen deposition. It may, therefore, be useful in the treatment of liver fibrosis in NASH.

Pulse polarographic determination of thiophanate methyl fungicide in relation to its soil adsorption study

Abstract Background The environmental pollution caused by the extensive use of the pesticide thiophanate methyl is of great concern, because it is a category III acute toxicant and a suspected carcinogen. Method A remarkably sensitive differential pulse polarographic method for the determination of thiophanate methyl has been developed. The method is based on the reaction of the fungicide with copper(II) perchlorate in the presence of butylmethylimidazolium bromide (ionic liquid) in acetonitrile. Results The reaction product exhibits an analytical useful diffusion controlled peak at −180 mV (vs SCE), and the thiophanate methyl has been determined in the linearity range 1.25 × 10−6 to 12.5 × 10−6 mol L−1 with a correlation coefficient of 0.997. To study the fate of this pesticide in soil and extent of surface and groundwater contamination, its adsorption on four soils of different soil characteristics has been studied using batch equilibrium technique. Conclusion The leaching potential, a measure of ground and surface water contamination, has been evaluated in terms of groundwater ubiquity score (GUS) and the value obtained is in the range 0.87 to 0.97, classifying it as non-leaching pesticide.

Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations

Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations

Corrosion characteristics of ZnNiCo ternary alloy electrochemically deposited by using different anodes

Corrosion characteristics, of ZnNiCo ternary alloy metallic coatings electrochemically deposited by using different anode shave been investigated. Analysis of corrosion characteristics was performed by using the polarographic methods and electrochemical impedance spectroscopy. Due to different values of oxygen overvoltage, each anode gives different cell voltage that increases in the order of MMO<Ti/Pt<BDD. Polarigraphic measurements showed the lowest corrosion rate (88 mm/year) of the coating deposited using Ti/Pt anode, while the corrosion rate for the remaining two coatings is approximately twice as large. The impedance measurements have shown two time constants that can be attributed to the dielectric properties of the layer of corrosion pro ducts at the coating surface and the coating layer itself. In concordance with polarigraphic measurements the resistance of both layers is approximately twice higher for the coating obtained using Ti/Pt anode.

Sorption of Cr (VI) Ions by Chlorine-containing Redox Polymers based on Weak-Base Polyamines.

Polarography method has been used to research the sorption of Cr (VI) ions by chlorine-containing redox polymers based on weak-base polyamines. The process has been reviewed in classic solutions of various concentration, at various pH, and involving various sorption duration. Comparative data has been obtained in relation to the extraction of chromium ions by anionites.

A new sensitive method for the determination of trace mercury by differential pulse polarography: Application to raw salt sample

A new indirect differential pulse polarographic (DPP) method is established for the trace determination of mercury(II). Because of its toxic effects on human health, trace determination of mercury is very important. An indirect method had to be used since no polarographic peak is observed in its direct determination. According to the standard potentials, the reaction between Sn(II) and Hg(II) was found suitable. The peak of Sn(II) at about −0.40 V is sharp, high and very reproducible, which enables the determination of low concentrations of Hg(II). For this purpose, to a known amount of Sn(II) present in the polarographic cell (acetic acid, HAc, pH 1–2), the unknown Hg(II) sample is added and the quantitative reaction takes place directly in the cell. The Hg(II) concentration is calculated simply from the decrease of the Sn(II) peak. The limit of detection (LOD) was found as 2 × 10−7 M for S/N = 3. Interferences of some common cations, such as Fe, Cd, Cu, Zn and Pb and anions have been investigated. Only Pb had an overlapping peak with Sn(II). This peak overlap was eliminated simply by working at pH 2 (HAc electrolyte), because of the shift of the Pb peak in the Ac complex to −0.7 V. This method was successfully applied to synthetic samples and raw salt sample taken from a salt lake in Turkey.

A New and Simple Method for the Simultaneous Determination of Fe, Cu, Pb, Zn, Bi Cr, Mo, Se, and Ni in Dried Red Grapes Using Differential Pulse Polarography

Dried grapes are consumed in Turkey in high quantities. It is a very important fruit because of its high content of vitamins and elements. A new and simple differential pulse polarographic (DPP) method for the trace element determination in dried grapes has been established. With this technique, it is possible to determine very low quantities of elements with high accuracy. The polarograms were taken in various electrolytes and pH values in the presence of digested grape sample. According to these results, nine trace element determinations were made in acetate, potassium carbonate, and ammonia electrolytes at various pH values, with or without EDTA depending to ions under consideration. It was possible to separate and determine Pb, Cu, and Cr simultaneously in potassium carbonate at pH 11 with only one sample addition. For separation and determination of Ni and Zn peaks, ammonia buffer, pH = 9.8, was found suitable. Simultaneous determination of Bi, Mo, and Fe could be made in HAc–NaAc buffer at about pH = 7 and in the presence of EDTA. Selenite could be determined in HAc–NaAc buffer from its hydrogen catalytic peak in the presence of Mo(VI).

Determination of the food dye carmine in milk and candy products by differential pulse polarography

As a basis for the development of a sensitive analytical method for the determination of carmine food dye, a study of the differential pulse polarographic reduction of carminic acid (CA) on a dropping mercury electrode was performed. For the analytical differential pulse polarographic method running at pH 2.0 Britton–Robinson (B–R) buffer solution (peak at −489 mV), the relationship between the peak current and CA concentration was linear in the range of 1 μM to 90 μM with a detection limit of 0.16 μM. The proposed electrochemical procedure was successfully applied to the determination of carmine food dye in spiked commercially available strawberry flavored milk. The method was extended to the determination of CA in candy and results were in agreement with that obtained by a spectrophotometric comparison method. A cyclic voltammogram of CA in 2.0 B–R buffer electrolyte was obtained on the dropping mercury electrode at pH 2.0 during potential scans from 0.00 mV to 1000 mV versus Ag/AgCl. From repetitive cyclic voltammograms, one cathodic peak at −500 mV and three anodic peaks on the reverse scan between approximately −340 mV and −460 mV were recorded. The influences of some other commonly found inorganic and organic salts on the determination of CA were also examined. The sufficiently good recoveries and low standard deviations for the data reflect the high accuracy and precision of the proposed differential pulse polarographic method.

Polarographic investigation on taxim-of in presence of NickelB(II)

A new, simple, accurate, polarographic method have been developed for the analysis of Taxim-of and Cobalt(II) in pharmaceutical dosage forms. It is possible to determine the cobalt(II) and Taxim-of in the range of 5.0 x 10 -7 M to 5.0 x 10 8 M and 0.74 to 7.4 µg/25ml. Well defined peaks at potentials -0.9V Vs SCE for Taxim-of and 1.0V Vs SCE for CO (ll) were