Method for lipoic acid measurement in biologically active additives by cathode voltammetry
SUBSTANCE: invention describes a method for lipoic acid measurement in biologically active additives by cathode voltammetry involving transferring a substance from a sample into a solution and taking voltammetric measurement; the cathode voltammetry is performed on a mercury-film electrode at potential -0.373 V of a relatively saturated silver-chloride electrode with borate buffer solution pH 9.18 at continuously current potential trace at 0.06 V/s with the determined lipoic acid content range from 4.5·106 to 1.1·10-3 mole/l.
EFFECT: improving sensitivity and expressivity of the method for measuring lipoic acid in tabletted BAAs by cathode voltammetry.
1 tbl, 1 ex, 3 dwg
The invention relates to the field of quantification of lipoic acid with antioxidant properties in biologically active food supplements. Method for determining cathodic voltammetry.
Lipoic acid (α-lipoic acid, 3-(4-carboxybutyl)-1,2-dithiolan, thioctic acid or Lipatova acid) is a coenzyme involved in the catalytic transfer reactions of hydrogen atoms and acyl groups, plays a major role in the metabolism of man and animals, is a powerful antioxidant.
Antioxidant properties of lipoic acid is due to the presence of two thiol groups in the molecule (Fig.1), as well as the ability to bind molecules free radicals and tissue iron, preventing its participation in the peroxide oxidation of lipids. It is known that lipoic acid not only has the independent antioxidant capacity, but also provides powerful support for the work of other antioxidant mechanisms in the body. In this respect, its protective effect is closely linked to the homeostasis in the system of glutathione and ubiquinone.
It is known that there is a complex of antioxidants, which can interact lipoic acid and maintain both lipid and aqueous antioxidant status, which is important for the treatment or prevention of various diseases, to�which notes the imbalance of redox cellular status, such as diabetes mellitus, liver dysfunction, etc.
On the basis of lipoic acid created a number of synthetic antioxidants to protect cells from oxidative stress in the form of biologically active food additives (BAA).
Effective and rapid method for determination of lipoic acid in pharmaceutical preparations is considered capillary electrophoresis with spectrophotometric method of detection (Sitton A., Schmid M. G., Gubitz G., Hassan Y. Aboul-Enein. Determination of lipoic acid in dietary supplement preparations by capillary electrophoresis // J. of Biochem. And Biophysic. Methods. - 2004. - V. 61, No. 2. - P. 119-124). In this method lipoic acid is determined in the UV region at 208 nm. The analysis time does not exceed 9 minutes. This method is used for determination of lipoic acid in the range from 0.8 to 2.5 mg/ml. the Method was developed for the determination of lipoic acid in dietary supplements diet food. The disadvantage can be considered low sensitivity of the determination of lipoic acid in dietary SUPPLEMENTS.
To ensure quality control of SUPPLEMENTS containing lipoic acid, it is necessary to develop a method for quantitative determination in her BAD. Currently, methods for the quantitative determination of lipoic acid in different objects are widely used electrochemical methods.
The closest to the subject of the invention is the voltammetric determination Lipaev�th acid in model solutions on glass-carbon electrode (G. K. Ziyatdinova, G. K. Budnikov, V. I. Pogoreltsev // Electrochemical determination of lipoic acid. Journal of analytical chemistry. 2004. T. 59. No. 3. Pp. 324-326). When the voltammetric determination of α-lipoic acid, the authors used stationary glass-carbon electrode on the background of 0.05 mol/l H2SO4while a distinct signal was observed at a potential of 0.72 V. the Range defined voltammetric contents lipoic acid ranged from 1.15·1-5up to 1.73·10-4mol/l on glass-carbon electrode.
The use of the terms in the prototype method does not provide the sensitivity of the determination of lipoic acid in real objects BAD that due to the introduction of error in the summed signal of the determination of lipoic acid through the influence of related components of the dietary Supplement.
New technical problem - increasing sensitivity and quick testing were method of determination of lipoic acid in tablet form SUPPLEMENTS the cathodic voltammetry. The task is achieved by the fact that lipoic acid is transferred from the pill form in the solution and carry out voltammetric determination using cathodic voltammetry. To develop methods for the determination of lipoic acid used the analytical signal recovery lipoic acid at a potential In -0.373 in borate �vernom solution pH 9.18 at a mercury-film electrode (RPE). Cyclic voltamperometry lipoic acid on the RPE is shown in Fig.2. The dependence of the gain current limit recovery lipoic acid from increasing its concentration in model solution linear. This area is located between the concentrations of 4.5·10-6mol/l to 1.1·10-3mol/l (Fig.3). The rate of potential sweep amounted to 0.06 In/s.
The limit of detection of lipoic acid 9.3·10-6mol/l are sufficient for use in assessing its quantitative content in the BUD.
Values of the limits of repeatability, reproducibility and critical range of concentration of lipoic acid at a confidence probability P=0.95 is shown in table.1.
Example 1. Determination of lipoic acid in tablet BAD "Lipoic acid".
One tablet triturated in a mortar to obtain a powder. The powder is weighed and transferred into a 50 ml flask, add 10-15 ml of borate buffer solution pH 9.18 and heated in a water bath at a temperature of 45-50°C for 10 minutes. After that, the solution was filtered through a paper filter, which was washed with buffer twice for 5 ml. Then in a quartz Cup with a capacity of 20 ml make 10.0 ml of the supporting electrolyte borate buffer solution pH 9.18, placed in the electrochemical cell for voltammetric analyzer (TA-2, Tomsk). Immersed in solution electrodes: and�dichotomy - mercury-film electrode, the auxiliary and the reference electrode - saturated chloride-silver. Registration background lines constantly spend in the current shooting mode with linear potential sweep rate 60 mV/s after the removal of oxygen from elektrokhimicheskoi cell with inert nitrogen gas for 15 minutes, in the range of potentials from 0 to -0.8 V. the Absence of peaks on voltamperometry and reproducible curves testified to the purity of the background. After obtaining satisfactory curves background contribute aliquot of filtrate lipoic acid a volume of 0.1 ml. Stirred solution of 10 with nitrogen gas, soothe with 20 and remove voltamperometry under the same conditions. The cathodic peak is recorded at a potential -0.373 V. the Concentration of lipoic acid was estimated by the height of the cathodic peak by the method of additives certified mixtures of lipoic acid by the standard technique.
The proposed method for the quantitative determination of lipoic acid is simple, does not require a lot of effort, a significant amount of chemicals and has a high sensitivity and rapidity.
The proposed method can be used for the quantitative determination of lipoic acid in dietary SUPPLEMENTS and dosage forms.
|Measurement range, mol/l||The limit of repeatability (relative value allowable difference between two measurement results obtained in one laboratory under conditions of repeatability), r, %||Critical range (relative value allowable difference between the highest and lowest of the three measurement results obtained in one laboratory under conditions of repeatability), CROf 0.95(3),%||The limit of Reproducibility (relative value allowable difference between two results|
measurements obtained in different laboratories), R, %
The method of determination of lipoic acid in dietary supplements by cathodic voltammetry, including the transfer of substances from the sample into the solution and voltammetric determination, wherein the conducting cathodic voltammetry at a mercury-film electrode at a potential -0.373 In a relatively saturated chloride-silver electrode on the background of borate buffer solution pH 9,18 when permanently current form of the potential sweep at a speed of 0.06 In/with the region defined�holding lipoic acid 4.5·10 6to 1.1·10-3mol/L.
SUBSTANCE: in agar plate which is in a Petri dish and inoculated with one of the fungal species of the genus Fusarium, circular holes are cut with the diameter of 8 mm, 0.05 ml of the working solution of the test preparation is applied into them, and placed in a thermostat at a temperature of 24.5-25.0°C, after 2-5 days depending on the type of fungus the diameter of the zone of growth inhibition of fungal mycelium is measured and the activity of the preparations is calculated according to the formula , and it is considered that when A=1 the fungicide is ineffective - the zone of growth inhibition is not formed (D=d), when A=2-3 the preparation activity is low, when A=4 it is average, and when A≥5 it is high.
EFFECT: invention provides accuracy of determining the activity of seed disinfectants and fungicides used in agricultural production.
SUBSTANCE: invention represents a method for preclinical study of cardiotropic antiarrhythmic drugs, involving determining the bioelectric parameters in isolated multicellular perfused preparations and measuring an action potential duration, differing by the fact that the isolated multicellular perfused preparations are presented by rat's pulmonary vein myocardium; the parameters are measured in three operation modes of the multicellular preparations; a resting potential is additionally measured; varying APD 90%, related APD 50%/APD 90%, a spontaneous shear velocity of the resting potential, the most positive membrane potential in the resting preparation, a spontaneous activity train repetition rate, spontaneous action potential train repetition and variability frequency, post-depolarisation number and intensity, as well as a shear membrane potential corresponding to the beginning of train activity are used to evaluate the signs of antiarrhythmic and arrhythmogenic action.
EFFECT: more reliable prediction of the antiarrhythmic action of the potential pharmacological agents and reduction of experimental phase time.
SUBSTANCE: invention relates to method of determining platelet resistance to acetylsalicylic acid (ASA) by impedance analysis of aggregation function of platelets in vivo, in which aggregation activity is analyses after incubation of biological material sample with ASA with application of aggregation inducer, and aggregation of platelets is induced by collagen in optimal concentration 2 mg/ml, and simultaneously with measurement of impedance determination of dynamics of platelet granules release is performed by luminescent method, where before carrying out aggregation samples are calibrated by means of adenosine triphosphate (ATP) standard, value of aggregation amplitude are determined in Ohms by obtained aggregatograms and obtained values are given points: values ≤6 correspond to 0 points, values 7-9 correspond to 1 point, values 10-12 correspond to 2 points, values >12 correspond to 3 points; after that, intensity of ATP release from platelet granules is determined in nmoles and obtained values are given points: values <0.5 correspond to 0 points, values 0.5-1.0 correspond to 1 point, values 1.0-1.5 correspond to 2 points, values 1.5 correspond to 3 points, and then resistance index (RI) is calculated by formula, value of IR parameter points to presence of aspirin-resistance of platelets.
EFFECT: carrying out fast complex diagnostics of platelet resistance to ASA with estimation of functional state of platelet granules before beginning treatment and possibility of preventing development of undesirable thrombotic or hemorrhagic complications.
2 dwg, 1 tbl, 2 ex
SUBSTANCE: claimed is application of fat emulsion for parenteral feeding as solvent for compounds which are poorly soluble in water. Fat emulsion contains in 1 l of solution: 30 g of refined soybean oil, 30 g of triglycerides with the average chain length, 25 g of olive refined oil, 15 g of purified fish oil.
EFFECT: obtaining solvent for compounds, poorly soluble in water, which makes it possible to determine parameters and spectrum of biological activity of novel compounds of chemical nature at the stages of pre-clinical and clinical tests, which does not change basic biological constants and possesses biological inertness.
2 tbl, 2 ex
SUBSTANCE: invention relates to biology, forensic and analytical chemistry and specifically to methods of determining procaine in blood plasma. The method comprises adding sodium fluoride to blood plasma containing procaine to achieve concentration of 10 mg/ml; treating the obtained mixture with acetone; separating the extract from the precipitate by filtering; evaporating acetone from the filtrate in an air current at room temperature; diluting the aqueous residue by adding water; saturating the obtained solution with ammonium sulphate; alkalising with an ammonium buffer solution to pH 9.0-9.5; extracting twice with portions of an organic extraction agent in the form of 30% camphor solution in methyl acetate, with ratio of the aqueous to the organic phase of 1:1 by volume; separating the organic extracts; combining; evaporating the solvent from the combined extract in an air current at room temperature; chromatographing the residue in a thin layer of silica gel STKH-1A on Sorbfil PTSKH-AF-A-UF plates, using a dichloromethane-ethanol mobile phase in ratio of 6:4 by volume; developing the chromatogram in UV light; eluting the analysed substance from the sorbent with a mixture of acetonitrile-methanol-0.025 M potassium dihydrogen phosphate solution with pH 3.0 in ratio of 10:10:90 by volume; chromatographing by HPLC method using a reversed-phase sorbent Nucleosil C18, a polar mobile phase acetonitrile-methanol-0.025 M potassium dihydrogen phosphate solution with pH 3.0 in ratio of 10:10:90 by volume and a UV detector; measuring optical density at wavelength 298 nm and calculating the amount of the analysed compound from the area of the chromatographic peak.
EFFECT: method improves sensitivity of determination.
3 tbl, 2 ex
SUBSTANCE: invention relates to analytical chemistry. The method is characterised by electrochemically concentrating benzoic acid on the surface of a graphite electrode for 90 s at electrolysis potential of (-0.500) V on a background of 0.1 mol/l sodium hydrogen phosphate, recording polarisation curves with linear potential sweep rate of 25 mV/s and determining concentration of benzoic acid from the peak height in potential range of 0.5-1.6 V relative to a silver chloride electrode.
EFFECT: method provides highly sensitive and rapid determination of benzoic acid in medicinal drugs.
3 ex, 6 tbl
SUBSTANCE: sample is applied on a paper filter, and standard calibration solutions of metronidazole in the concentration range of 10-100 mcl are radially applied on the same filter. The filter is processed with a developing agent containing 5% potassium hydroxide and acetone taken in ratio 2:1 and thermostated at 100°C until coloured spots are visible. A colour intensity of the sample spot is compared to the colour of the spot colour of the reference calibration solutions to determine the metronidazole concentration in the analysed sample.
EFFECT: method enables the fast and reliable monitoring of the metronidazole content and the timely correction of the therapeutic process.
SUBSTANCE: invention refers to medicine, namely to studying and analysing medical preparations, and can be used for standardising herbal raw materials. A method for identification and qualitative measurement of chlorophyll, carotinoids and hydroxycinnamic acids in a combination in great nettle leaves involves a 1-hour fractional extraction, 30 min each of the ground raw material having a particle size of 1.0 mm on a water bath at a temperature of 100°C with 70% ethanol in a ratio of the herbal raw material to the extractant of 1:100, the combination of the extracts and reduction to 100 ml with a solvent, dilution of the prepared solution in a ratio of 2:25 in 96% ethanol, measuring an optical density of the solution in relation to 96% ethanol at maximum absorption 328±1 nm, 442±1 nm and 667±1 nm, calculation of the total content of hydroxycinnamic acids equivalent to chlorogenic acid, carotinoids equivalent to violaxanthin and chlorophyll in the percentage equivalent to an absolute dry mass of the raw material by formulas.
EFFECT: method provides availability, simplicity, efficiency and low error of measurement.
3 dwg, 1 ex
SUBSTANCE: method of determining fat-soluble vitamins A, D2, E and β-carotene which are present at the same time includes separating the fat-soluble vitamins from a substance by extraction with 96% ethanol, separating the alcohol extract of vitamins using a separating funnel, successive chromatography using Sorbfil PTSKH-P-A silica gel plates on a polymer substrate using two eluents with a different range, time of saturating the chamber with eluent vapour of 20 minutes and elution time of 55 min; drying the plates at temperature not lower than 80°C in a temperature-controlled chamber for 3-5 min, treating the plates with a developer - 5% alcohol solution of phosphatomolybdic acid; according to the invention, the eluents used are hexane:chloroform (19:1) and hexane:chloroform (3:1), and detection of the chromatographic zone of β-carotene is carried out before treating the plates with a developer in day light.
EFFECT: simpler and faster process of determining fat-soluble vitamins.
10 dwg, 3 ex
SUBSTANCE: invention relates to medicinal drug quality control and provides a method of authenticating and determining the quantitative content of benzethonium chloride in medicinal drugs, which includes separating components of the drug via high-performance liquid chromatography, where the eluent used is a mixture of acetonitrile, tetrabutylammonium hydrophosphate, disubstituted potassium phosphate and water, with content of tetrabutylammonium hydrophosphate of 2.5 mM, content of disubstituted potassium phosphate of 5 mM, wherein separation of the components of the drug is carried out with column length of 125 mm.
EFFECT: high accuracy and faster analysis since there is no need for special sample preparation.
SUBSTANCE: gas analyser (fig. 1) comprises electrolytic chamber 1 with capillary 2 extending to gas analyser cathode surface. Said chamber and capillary are filled with electrolyte. Device comprises anode 3 in direct contact with chamber electrolyte and cathode 4 arranged at gas analyser surface nearby capillary outlet area. Cathode and capillary are isolated from ambient medium by selective-permeability ring-shape membrane 5 attracted to cathode and capillary and locked at gas analyser cathode surface. Said membrane is attracted and locked by cover 6 composed of turned over cup with axial bore in its bottom and coupled with coupling nut 7. Said membrane is attracted by its edges squeezed between cover bottom and seal ring 8 arranged inside said cover and features preset modulus of elasticity and depth. Membrane locking is ensured by said cover over closed line with the help of rib shaped to blunt angle. Conductors 9, 10 are designed to derive output signal from anode 3 and cathode 4. Said conductors are connected to gas analyser output signal recorder 11. The second version (fig. 2) differs from said first one in that membrane is attracted and locked by different elements. Electrolytic chamber 1 with capillary 2, anode 3 and cathode 4, selective-permeability ring-shape membrane 5 attracted to cathode and capillary and locked at gas analyser cathode surface by the rib in closed line. Note here that at joint between membrane and cover, the latter features low friction factor. Device comprises coupling nut 7. Attracting element 8 is arranged inside turned cover 6 and composed of over cup with axial bore in its bottom. Cover 6 and attracting element 8 are articulated. Coupling nut 7 is connected with attracting element 8. Said seal ring 9 is inside element 8 and features preset modulus of elasticity and depth Membrane 5 is attracted to cathode and capillary by element 8 with the help of nut 7 so that membrane edges are squeezed between attracting element bottom and seal ring 9. Conductors 10, 11 tap output signal from said anode and cathode and are connected to output signal recorder 12. The third version (fig. 3) differs from said first one in that membrane is attracted and locked by different elements. It differs from above versions in the following. Electrolytic chamber 1 with capillary 2, anode 3 and cathode 4, selective-permeability ring-shape membrane 5 attracted to cathode and capillary and locked at gas analyser cathode surface by the rib in closed line. Device includes coupling nut 7 arranged inside cover 6 and rigidly coupled therewith. Attracting element 8 composed by washer is arranged inside coupling nut 7, at its bottom, while seal ring 9 with preset modulus of elasticity and depth is arranged therein. Note here that at joint between element 8 and nut 7 features to friction factor. Said membrane is attracted to element 8 so that its edges are squeezed between element 8 and ring 9. Conductors 10, 11 tap output signal from said anode and cathode and are connected to output signal recorder 12.
EFFECT: simplified and reliable design, efficient sealing, lower membrane material input.
5 cl, 3 dwg
SUBSTANCE: invention relates to electroanalytical chemistry and can be used to analyse drinking water surface water and other water bodies. A method for voltammetric determination of phenol in water and water bodies using a three-electrode system, which includes pre-modifying electrochemical treatment of a glass-carbon indicator electrode of the system, measuring phenol concentration in the water, including electrochemical deposition of phenol on the modified surface of the indicator electrode from the analysed water, subsequent electrooxidation of phenol while varying potential of the indicator electrode, detecting an analytical signal on the current versus voltage curve, identifying a phenol peak on the current versus voltage curve and determining phenol concentration from the value of the phenol peak, characterised by that pre-modifying electrochemical treatment of the indicator electrode is carried out in 0.2 M aqueous ammonium sulphate solution with addition of acetone in volume ratio of 19:1, respectively. A method in which electrodes of the measurement system - indicator, comparison and auxiliary electrodes - used are identical glass-carbon rod electrodes, and where pre-modifying electrochemical treatment of the indicator electrode also includes treating the surface of the comparison electrode and the auxiliary electrode in 0.1 M aqueous potassium hydroxide solution with addition of acetone in volume ratio of 19:1, respectively.
EFFECT: improved method.
SUBSTANCE: method of determining aflatoxin B1 includes the following operations: transferring aflatoxin B1 from a sample into a solution and carrying out voltammetric accumulation of mycotoxin in a stirred solution for 30 s at electrolysis potential of (0.0±0.05)V relative to a saturated silver chloride electrode on an ammonium chlorate (NH4ClO4) background, pH 2.0-3.0, followed by detection of anodic peaks with sweep rate of 30 mV/s, and determining concentration of aflatoxin B1 from peak height in the range of En=(0.625±0.045)V by standard addition method.
EFFECT: invention enables use of electrodes made of nontoxic material and determination of aflatoxin B1 by anodic stripping voltammetry in the presence of dissolved oxygen without further addition of a reducing agent to the background electrolyte, wider range of determined concentrations and a technique for rapid evaluation of aflatoxin B1 in 30-40 minutes.
2 tbl, 2 ex, 1 dwg
SUBSTANCE: method of mercury identification by cathode-anode voltammetry with the application of an electrode and background solutions includes the following succession of actions. First, a glassy carbon electrode is kept in a background solution at a potential from -0.4 to - 0.7 V for 120 s, then it is switched to a potential from + 0.4 to + 0.5 V and is kept for 10 s with the following registration of voltamperogram with a linear involute of the potential in the range from 0.4 V at 100 mV/s and a peak of the mercury reduction, observed at the potential in ranges (-0.05-0.05) V, and linear dependent on the mercury concentration in water solutions. A mercury signal is registered and evaluated by a method of additives of certified solutions relative to a saturated silver chloride electrode.
EFFECT: invention makes it possible to determine a small quantity of mercury in a water solution by the method of cathode-anode voltammetry.
SUBSTANCE: method of molybdenum identification includes the determination of a complex compound of molybdenum with diethyldithiocarbaminate by cathode voltammetry . According to the invention 0.02 ml 1·10-4 M of sodium diethyldithiocarbaminate are introduced into a universal buffer solution, then a sample, which contains molybdenum is introduced, the solution is mixed for 10-30 s, a potential of electrolysis +0.4 V is supplied for 180 s on a glassy carbon electrode and current of a molybdenum peak is registered at a speed of the potential involute of 100 mV/s. A signal of molybdenum is registered and evaluated by a method of additives of certified solutions relative to a saturated silver chloride electrode.
EFFECT: invention makes it possible to reduce a lower boundary of determined contents of molybdenum by 2-3 orders.
2 dwg, 1 tbl
SUBSTANCE: lactic acid is transferred from a sample into a solution and voltammetric accumulation of lactic acid in the stirred solution is performed while bubbling with an inert gas for 30 s and with electroaccumulation potential of 1.2-1.4 V relative to a saturated silver chloride electrode on a background electrolyte of 0.1 M Na2HPO4, followed by detection of cathode peaks in differential mode of recording voltamperograms with potential sweep rate of 30-40 mV/s; concentration of lactic acid is determined from peak height in the potential range of 0.25-0.40 V by a standard addition method.
EFFECT: method is simple, does not require a large amount of reactants and labour costs.
2 ex, 1 tbl
SUBSTANCE: method of determining lithium ascorbate in a drug formulation includes a sample preparation step and voltammetric determination. The invention involves conducting anodic voltammetry on a glassy-carbon indicator electrode at potential of +0.24 V relative a saturated silver chloride electrode on a background of 0.1 mol/dm3 potassium chloride, with a direct current form of potential sweep at a rate of 30 mV/s with the region of the determined content of lithium ascorbate from 2.1·10-4 to 17·10-6 mol/dm3.
EFFECT: efficient sensitive and rapid determination of lithium ascorbate in a drug formulation by voltammetry.
1 ex, 1 tbl, 2 dwg
SUBSTANCE: method of determining calcium ascorbate in biologically active additives includes a sample preparation step and voltammetric determination. The invention involves conducting anodic voltammetry on a glassy-carbon indicator electrode at potential of +0.32 V relative a saturated silver chloride electrode on a background of 0.1 mol/dm3 potassium chloride, with a direct current form of potential sweep at a rate of 30 mV/s with the region of the determined content of calcium ascorbate from 1.5·10-5 to 6.7·10-4 mol/dm3.
EFFECT: efficient sensitive and rapid determination of calcium ascorbate in biologically active additives by voltammetry.
1 ex, 1 tbl, 2 dwg
SUBSTANCE: method for voltammetric determination of Fe2O3 nanoparticles on a carbon paste electrode according to the invention involves electrochemical conversion of Fe2O3 nanoparticles on a carbon paste electrode in a background electrolyte of 0.02 mol/dm3 trilon B solution (pH 3-4) at electrolysis potential of (-0.12±0.01)V relative a silver chloride electrode, followed by detection of the anode peak in direct current conditions of recording voltage versus current curves with potential sweep rate of 80-90 mV/s, wherein concentration of Fe2O3 is determined from the height of the anode peak in the potential range of (-0.12±0.01)V.
EFFECT: invention enables to obtain an analytical signal for electro-conversion of Fe2O3 nanoparticles, which in turn enables to perform identification and quantitative determination of Fe2O3 nanoparticles on a carbon paste electrode using a voltammetric technique.
3 dwg, 1 ex
FIELD: measurement equipment.
SUBSTANCE: invention is aimed at detection of rhenium in rocks and ores by kinetic inversion-voltammetric method and may be used in different industries to detect content of concentrations of various metal ions in solutions. The method according to the invention includes detection of rhenium on the background of 0.1 M H2SO4 with addition of 0.03 ml of 30% H2O2 by the method of kinetic inversion voltamperometry, when electric concentration of rhenium is carried out in a mercury film electrode with subsequent registration of cathode peaks, taking voltamperegrams at the speed of potential deployment of 100 mV/s, at the same time the concentration is determined by the height of the cathode peak in the range of potentials from 0.0 to 0.20 V by the method of addition of certified mixtures.
EFFECT: invention makes it possible to exclude using highly toxic materials when detecting ions of rhenium (VII), and also provides for higher accuracy, resolution and express nature of determination.
1 ex, 2 tbl, 2 dwg
FIELD: analytical chemistry.
SUBSTANCE: substance is subject to preliminary concentrating during 300 sec at potential of electrolysis of (-1,2) V by using special device. Glass-carbon electrode is used as working electrode. Polarization curves are registered subsequently at ac potential development at speed of 300 mV/sec. Concentration of amiodarone is found from peak value within the potential range of 0,1-0,3 V relatively chlorine-silver electrode in 0,005 mole/l nitrate ammonium solution that is prepared on the base of 0,015 mole/l sodium hydrocarbonate solution.
EFFECT: improved sensitivity of method.
1 dwg, 4 tbl