Method of express-identification of cobalt (ii) and copper (ii) in water-salt solutions for environmental objects analysis
SUBSTANCE: invention can be used for semi-quantitative determination of cobalt (II) and copper (II) concentration is natural, sewage waters and various liquids under field conditions. Method includes filling glass tube with internal diameter 0.5 cm with Na-form of cation exchanger KB-2E-10 with weight 0.2 g, with further filling with analysed solution, which contains added to it sodium nitrate with concentration 1 mole/l and calcium nitrate to create medium, and estimation of cobalt and copper concentration by length of coloured zone of cation exchanger with the following content of components after tube filling, wt %: cation exchanger KB-2E-10 - 0.8; sodium nitrate - 8.5; calcium nitrate - 0.25; water - the remaining part.
EFFECT: increase of accuracy and reliability and simplification of analysis.
1 ex, 2 dwg
The invention relates to the field of analytical chemistry, namely the development of rapid tests, and can be used for semiquantitative determination of the concentration of cobalt(II) and copper(II) in natural, waste water and various liquids in the field.
Method rapid determination of cobalt(II) and copper(II) in the presence in the aqueous solution includes a test indicator tube based on carboxylic cation exchanger KB-2E-10 to the sodium form, and as substances to create environment - nitrates of sodium and calcium.
Known (Patent RF 2223488, G01N 31/22, G01N 21/78, 10.02.2004) an indicator composition for the determination of copper(II) in aqueous solutions containing sorbent, the reagent substance to create an environment and water, characterized in that it comprises as a sorbent - anion exchange resin an-31 in the sulfate form, as an analytical reagent 4-(2-pyridylazo)-resorcinol (PAR), and as substances to create environment - sulfuric acid. The disadvantages of this indicator composition is the use of expensive reagent VAPOR, which leads to additional costs, and the lack of determination of copper and cobalt from a mixture.
Known (Patent RF 2002129681, G01N 31/22, 10.05.2004) an indicator composition for the determination of cobalt(II) in aqueous solutions containing sorbent, nitroso-R-salt, a substance to create an environment and water, otlichalis�, what contains as the sorbent cation exchanger KB-2-3T, and as substances to create environment - sodium acetate. Determination of cobalt by this method interferes with copper. Method for determination of copper and cobalt in the presence of the proposed method is unknown.
The authors Petrova V. V., Bobkova, L. A. [Test-flat tube-based macrosector carboxylic cation exchanger KB-2E for determination of impurities Co2+and Cu2+in water-salt solutions // proceedings of XIII all-Russian scientific-practical conference named after Professor L. P. Kulev of students and young scientists "Chemistry and chemical engineering in XXI century", may 14-17. 2012. S. 269-271] the described method of determination of impurities of Cu2+and Co2+at their joint presence in water-salt solutions using a test indicator tube based macrosector carboxylic cation exchanger KB-2E-10, selected as a prototype.
The disadvantages of this method are:
1. Adding a large number of background electrolyte of sodium nitrate to create an environment and, as a result, complication of the analysis.
2. The deletion of a large sample volume (100 ml), which increases the time of analysis.
3. The use of tubes with a diameter of 0.7 cm, which gives less contrast chromatographic separation zones ions of cobalt(II) and copper(II).
4. Show single� the result of the segregation of ions with the concentration of cobalt(II) and copper(II) ~30 mg/L. The ability to determine low concentrations of impurities not specified.
The object of the present invention is a method of rapid determination of cobalt(II) and copper(II) in water-salt solutions for the analysis of environmental objects to reduce the detection limit, reduce sample volume and time analysis. The technical result of the invention allows to determine the cobalt and copper at the same time without adding additional reagents. This can simplify the chemical analysis and reduce the time of the meeting.
Method rapid determination of cobalt and copper in water-salt solutions comprising a glass tube filled with Na-form cation exchanger KB-2E-10, sodium nitrate and calcium(II) for the creation of the environment, water, characterized in that is used a glass tube with an inner diameter of 0.5 cm, with a mass of cation exchange resin KB-2E-10 - 0.2 g, and the concentration of sodium nitrate is 1 mol/L. the Reagents used in the following ratio of components, wt.%:
The cation exchanger KB-2E-10 - 0,8
Sodium nitrate - 8,5
Calcium nitrate - 0,25
Water - the rest.
Copper(II) and cobalt(II) are the normalized components of natural waters. The maximum allowable concentration of Co2+in natural waters is 0.1 mg/l, a Cu2+1 mg/l. studies have shown that microsaccades carboxyl cationite KB-2E-10, synthesis�Rowan Kemerovo LLC "Tokem" on the basis of polymetacrylate and devicelog ether of diethylene glycol (DADAG) has a high affinity to ions of Co 2+and Cu2+. This allows the use of the sorbent as the active filler test indicator tubes for the determination of these ions in water-salt solutions.
For the determination of cobalt(II) and copper(II) sample analyte solution volume of 25 ml at pH ~4.5 and containing 2,125 g NaNO3and 0,059 g Ca(NO3)2passed at a rate of 1 ml/min through a glass tube with an internal diameter of 0.5 cm, filled with Na-form cation exchanger KB-2E-10 to a height of 4 cm (m=0.2 g). When passing the solution through a layer of bright grains of the resin occurs, the coloring layer of a sorbent characteristic for each ion color. The length of the colored zone depends on the concentration of the analyte. The content of ions of cobalt(II) and copper(II) in the sample solution is calculated according to the calibration graph (Fig.1), for construction of which we take aliquots of a standard solution of cobalt(II) and copper(II), is passed through the sorbent and measure the length of the painted area.
The dependence of the analytical signal (the length of the colored zone) linear in the concentration range for copper(II) - (0,95-9,53) mg/l, and cobalt(II) - (0,88-8,85) mg/l (Fig.1). Linearity is confirmed by the correlation coefficients close to unity.
The limit of detection of copper ions(II) amounts to 5.19 mg/l, and cobalt(II) - 3,15 mg/l. However, the qualitative determination of these ions is possible at the level of the MPC.
Example determine�t of copper(II) and cobalt(II) in aqueous salt solutions. In the sample analyzed solution volume of 25 ml, containing a mixture of ions of cobalt(II) and copper(II), add 2,125 g NaNO3and 0,059 g Ca(NO3)2. Adjusted the pH of the test solution to 4.5 by the addition of nitric acid or sodium hydroxide. The resulting solution is passed at a rate of 1 ml/min through a glass tube with an internal diameter of 0.5 cm, filled with Na-form cation exchanger KB-2E-10 to a height of 4 cm (m=0.2 g). When passing the solution through a layer of bright grains of the resin occurs, the coloring layer of a sorbent characteristic for each ion color. Measure the length of the colored zone of the cation exchange resin for each ion separately. The length of the colored zone depends on the concentration of the analyte. The content of ions of cobalt(II) and copper(II) in the sample solution is calculated according to the calibration equations:
- for Cu2+y=x 0,34+1,78(R2=0,99)
for Co2+: y=0.25 x+0,77(R2D =0.99),
where x is the concentration of metal ion in solution, R is the correlation coefficient.
Advantages of the invention consist in the possibility of determination of cobalt(II) and copper(II) at their joint presence in solution (Fig.2 - formation of the colored zones of ions of cobalt(II) and copper(II) to test the indicator tube-based cation exchanger KB-2E-10 with separate (a, b) and co-presence (b) in water-salt solutions) without adding additional reagents. This allows accelerated�tit chemical analysis and reduce the time of the meeting.
(Fig.2: and. the upper part of the blue color; b. top - pink V. top - blue, bottom - pink color).
Method rapid determination of cobalt and copper in water-salt solutions comprising filling a glass tube with an inner diameter of 0.5 cm Na-form cation exchanger KB-2E-10 weight - 0.2 g, with subsequent filling of the analyzed solution containing added sodium nitrate concentration of 1 mol/l and calcium nitrate to create an environment, and an estimate of the concentration of cobalt and copper along the length of the colored zone of the cation exchange resin with the following contents after filling the tubes, wt.%:
The cation exchanger KB-2E-10 - 0,8
Sodium nitrate - 8,5
Calcium nitrate - 0,25
Water - the rest.
FIELD: measurement equipment.
SUBSTANCE: invention relates to methods of indicator detection of trace amounts of explosives and components of explosives on the basis of three groups of compound classes: nitroaromatic compounds; nitramines and nitroesters; ion nitrates. The method of express detection of explosives on the basis of a set of chemical indicators for three groups of classes of nitrogen-containing compounds includes using a reactive indicator material with reagents, previously applied in dosed quantity onto a carrier, besides, the reactive indicator material is a carrier with immobilised azocomponent of Griess reagent, which is in solid chemically modified protected form with covalently bound amides.
EFFECT: increased sensitivity and reliability, as well as faster detection.
4 cl, 4 ex, 1 tbl
SUBSTANCE: method of determining iron (II) includes preparing a sorbent and an iron (III, II) solution; adding hydroxylamine solution to reduce iron (III) to iron (II) and extracting iron (II) from the solution with the sorbent; converting the iron (II) into a complex compound on the surface of the sorbent; separating the sorbent from the solution; measuring the diffuse reflection factor of the iron (II) surface complex and determining content of iron using a calibration curve. The sorbent used is silica which is successively modified with polyhexamethylene guanidine and 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5',5"-disulphonic acid (Ferene S), and the diffuse reflection factor is measured at 600 nm.
EFFECT: low detection limit and wide range of determined iron content.
SUBSTANCE: method includes pretreating a sample with an inorganic reagent and determining silicon using a spectrometric method based on a blue-coloured silicon-molybdenum complex followed by re-calculation for silicon dioxide, wherein the reagent used is 20% borofluorhydric acid and treatment is carried out at 70±2°C for 40 minutes.
EFFECT: high selectivity of analysis.
SUBSTANCE: claimed is reagent indicator truncated cone, which contains flow hollow profile, inside which sorbent with immobilised on it chromogenic reagents, is placed, with smaller base being input hole of truncated cone, overall dimensions of which are selected by the following dependences: ds = 0.25÷2.5, dl = (4÷50)·ds, ht.c = (8÷100)·ds, where ds and dl are diameters of smaller and larger bases of truncated cone, mm; ht.c is height of truncated cone, mm.
EFFECT: expressivity and increase of sensitivity of ion identification.
2 dwg, 8 ex
SUBSTANCE: in order to extract iron (III) from water solutions diphenylguanidine (DPG) is applied as the first organic reagent. As the second organic reagent, salicylic acid (SA) is applied, and as solvent of organic phase chloroform is applied. In organic phase complex with molar component ratio DPG: Fe3+:SA, equal 1:1:1, is extracted. Process of iron (III) extraction is carried out at medium acidity pH=1.5-2.5 with the following detection of iron (III) by trimetric method.
EFFECT: invention makes it possible to increase selectivity and simplify process of extraction and detection of iron from water solutions.
2 cl, 5 dwg, 1 ex
SUBSTANCE: invention relates to field of analytical chemistry, namely to express-detection of explosive substances (ES) based on organic peroxides. Method is based on fixation of hydroxen peroxide, released in the process of explosive substance decomposition by indicator method. For this purpose change of indicator colour is fixed within 1 minute after contact with solid-phase material, possessing function of surface acidity and providing decomposition of ES to hydrogen oxide. Application of claimed method simplifies analysis of cyclic peroxides due to reduction of the number of analysis stages, as well as to elimination of liquid reagents, including concentrated acids and organic solvents.
EFFECT: invention provides carrying out express-analysis of trace quantities of peroxide ES outside laboratory in wide range of climatic conditions.
6 cl, 2 tbl, 7 ex
SUBSTANCE: invention describes an indicator composition for the detection of disinfectants with an active substance based on quaternary ammonium compounds on surfaces of subjects and detection of disinfection completeness by aerosol spraying, which contains a 0.5-1.5% solution of trinitrotoluene in monoatomic alcohol, with propyl alcohol being applied as the monoatomic alcohol.
EFFECT: convenience and safety of application, increased term of working capacity and interval of application temperatures, protection of the environment, possibility of application at work on vertical, inclined and horizontal surfaces.
SUBSTANCE: indicator testing means for determining content of N-methylaniline in hydrocarbon fuels is neutral aluminium oxide with potassium ferricyanide immobilised on the surface thereof, moulded in form of pellets. The method of determining content of N-methylaniline in hydrocarbon fuels using said indicator testing means is carried out based on colour change thereof after coming into contact with a sample of the analysed sample.
EFFECT: reliability of determining lower concentrations of N-methylaniline in hydrocarbon fuels.
2 cl, 1 tbl, 2 ex
FIELD: measurement equipment.
SUBSTANCE: invention relates to nondestructive examination, to study of metal properties and is intended for confirmation of exhaustion of protective properties of heat-resistant diffusive coatings on details made of carboniferous heat-resistant alloys. The method of confirmation of exhaustion of protective properties of heat-resistant diffusive coatings on details made of carboniferous heat-resistant alloys by change of physical and chemical properties of the surface layer of heat-resistant diffusive coatings during operation in conditions of high temperature, comprises application of reagent on the coating surface, and the fact of exhaustion of protective properties of the heat-resistant diffusive covering is witnessed visually by change of colour of the surface of heat-resistant diffusive coating with formation of carbon and black oxides during the process of chemical reaction between carbide phases, forming in the surface layer of the heat-resistant diffusive coating at the late stages of operation, and reagent.
EFFECT: simplicity, reliability and reliability of tests is achieved.
1 ex, 5 tbl, 10 dwg
SUBSTANCE: invention refers to medicine and describes using resorufin and/or toluidine blue used as an organic oxidation-reduction colouring agent, one or more polyols, glycerol, and water introduced into gelatine and/or hydroxyethylstarch, and/or methlcellulose used as additives, as an oxygen indicator. The indicator is configured so that an oxygen-sensitive product stays visible.
EFFECT: declared invention provides the light- and heat-sensitive visibly discolouring oxygen indicator.
19 cl, 6 tbl, 10 ex
SUBSTANCE: in the method for photometric determination of chromium (III) in pure salt solutions, which includes conversion to a complex compound in xylenol orange in a weakly acidic medium, chromium (III) solution with pH 3.0-3.8 is mixed with a 200-fold amount of xylenol orange and a 200-fold amount complexion III and 0.1-0.2 ml surfactant solution. The surfactant is obtained by adding up to 100 ml water to 0.2 g gelatine. The volume of the solutions is then increased to 10 ml with water, followed by heating on a water bath at 60-80°C for 15 minutes.
EFFECT: invention increases sensitivity of photometric determination of chromium.
1 dwg, 4 ex
SUBSTANCE: method of determining concentration of grafted amino groups on the surface of mineral filling agents includes preparation of acetylating solution by mixing initial components, its addition to weighed portion of modified mineral filler sample, exposure for quantitative realisation of reaction, titration with alkali solution in presence of indicator, calculation of concentration of amino groups by difference of results of idle titration and sample titration. As acetylating solution used is 0.5-0.6 M solution of acetic anhydride in mixed solvent dichloroethane-pyridine in ratio from 0.5:1-2:1, which contains 0.025-0.15 mol/l of chloric acid as catalyst. 0.5-0.6 M of acetylating solution in mixed solvent, containing chloric acid, is added to weighed portion of modified mineral filler, ratio of weighed portion of sample weight to volume of acetylating solution constitutes 1:4-1:5, after which it is exposed and hydrolysing mixture, consisting of dimethylformamide, pyridine, water, taken in ratio 6:3:1 respectively, is added. After that, obtained mixture is centrifuged to separate residue.
EFFECT: simplification and extension of assortment of analysed materials, containing grafted amino groups on the surface of mineral fillers.
13 ex, 1 tbl
FIELD: measurement equipment.
SUBSTANCE: invention relates to a measuring method of variations of fluorescence intensity of voltage-sensitive fluorochrome depending on a potential gradient or ionic strength, which involves addition to the voltage-sensitive fluorochrome of an ionising compound to induce variation of potential or ionic strength, as well as addition of vitamin E and/or cholesterol to increase variation of potential or ionic strength as to voltage-sensitive fluorochrome. Besides, the invention relates to a potential measuring method of actions of cultivated cardiomyocytes.
EFFECT: invention provides measurement of fluorescence intensity of voltage-sensitive fluorochromes or voltage-dependent quantitative variations of their fluorescence intensity without using any such materials (membrane carriers), as cells or two-layer lipidic liposomes.
10 cl, 3 ex, 5 dwg
SUBSTANCE: method includes taking of a sample, processing the sample with an excess of diazotised sulfanilic acid in an alkaline medium, measurement of the optic density of the coloured solution on an analytic wavelength and calculation of the total content of phenols in terms of elementary phenol, with a reaction between the phenols and diazotised sulfanilic acid being carried out at pH value =7.2÷8.5, the reaction mixture is held at a temperature T=20÷25°C, for not less than 10 min, the optic density is measured in the field of the wavelength λ=340÷370 nm.
EFFECT: invention ensures an increased accuracy of photometric determination of the total content of phenols in terms of elementary phenol.
SUBSTANCE: diagnostic test element (110) for the detection of an analyte in a sample (126) of a body fluid, in particular whole blood with the volume not less than 2 microlitres, contains a test field (116) with a reagent-indicator, where the reagent-indicator is capable of feeling a detected change, in particular an optic change, in case of the analyte presence. The test field (116) includes a detector layer (118), containing the reagent-indicator, where the detector layer contains particles (137). 90% of all particles (137) of the indicator layer (118) have the actual size smaller than 10 microns. The diagnostic test element (110) contains a bearing element (112), which has a transparent region (114), where the test field (116) with its detection side (120) is partially applied on the transparent region (114).
EFFECT: detected change is an optically detectable change, where an optic detector with spatial resolution is applied for the detection of the detected change.
9 cl, 8 dwg, 1 tbl, 2 ex
SUBSTANCE: invention relates to analytical chemistry, namely to photometric determination of small concentrations of iron (III) in solutions of pure salts. The method includes conversion of iron (III) in a complex compound with an organic reagent and a surface-active substance in a mildly acidic medium by heating the above on water bath with following photometry of the obtained solution, and to a solution of iron (III) with pH 3.9-.5.2 added is 50-fold quantity of an organic reagent, represented by xylenol orange, 1.8-2.2 ml of a surface-active substance in the form of a 2% solution of ETHAL LA-7, and water to 10 ml of the volume with the following heating on water bath at a temperature of 60-80°C for 15 min and addition of 1 ml of acetone into the obtained solution.
EFFECT: invention makes it possible to increase the analysis sensitivity.
SUBSTANCE: invention relates to analytical chemistry, particularly to methods of determining benzoic acid, and describes a method for quantitative determination of benzoic acid from a methyl derivative thereof - methyl ether in aqueous matrices with determination sensitivity of 5.0·10-5 mg/cm3 with determination error of not more than 25%. The method is characterised by that quantitative determination of benzoic acid is carried out using a chromatographic method with flame-ionisation detection and includes the following steps: extraction concentration of an analyte with benzene in water samples acidified with 25% sulphuric acid solution to pH 1-3 while adding sodium chloride until a saturated solution is obtained, conducting a benzoic acid methylation reaction with diazomethane to obtain a derivative - methyl ether of benzoic acid and determining the formed methyl ether of benzoic acid by a chromatographic method with flame-ionisation detection.
EFFECT: method provides high sensitivity, selectivity and easy implementation during quantitative determination of benzoic acid in aqueous media and enables use thereof in practice in factory analytical laboratories, central laboratories of chemical companies and chemical-toxicology laboratories.
1 ex, 3 tbl
SUBSTANCE: group of inventions relates to analytical chemistry and can be used to indicate the end of the service life of a filter cartridge. The chemical sensor has a film which includes a film body which reacts to the presence of a chemical by changing colour, wherein the film body comprises: a detection layer; a barrier layer; a reflecting layer between the barrier layer and the detection layer, and a semi-reflecting layer on the side of the detection layer opposite to the reflecting layer. The barrier layer has a main surface attached to the film body in given regions of the sensor, but inert to the detection layer to prevent change of colour in the film body in the region lying in a direction which is perpendicular to the main surface of the barrier layer. The group of inventions also relates to a filter cartridge having said sensor, and a respirator having one or more of said filter cartridges.
EFFECT: group of inventions increases accuracy and reliability of analysis by providing clear contrast between original and signalling colours of the sensor.
17 cl, 3 dwg, 1 tbl, 3 ex
SUBSTANCE: group of inventions refers to medicine and may be used for detecting biological pathogens in a sample. A clinical indicator unit for detecting biological pathogens comprises a carrier foldable to form two opposite sheets. The inner side of the first sheet of the carrier comprises a contact surface of the sample and an absorbent pad, while on the inner side of the second sheet, there is an indicator surface opposite the contact surface; the indicator surface contains a solvatochromic stain discolouring if a bacterial pathogen is found in the test sample. The unit also comprises a results windows on the outer surface of the second sheet with the absorbent pad engaging a stained reaction zone if the first sheet is folded with the second one. The group of inventions also refers to a version of the above unit wherein the first and opposite second carriers are the two sheets or parts of the same first carrier folded to face each other, and to a method for using the above unit for bacterial infection analysis.
EFFECT: group of inventions enables fast and easy bacteria detection in the sample, and also provides differentiating between bacterial and viral pathogens.
16 cl, 6 dwg, 1 tbl, 9 ex
SUBSTANCE: invention can be used to determine content of iron (II) in solutions of pure salts containing iron (II) in very low concentrations. The method involves converting iron (III) into a complex compound with an organic reagent in a weakly acidic medium. The iron (II) solution with pH 2-5 is mixed with 200-300 times the amount of the organic reagent which is Congo red, 0.2-0.4 ml surfactant solution in form of a 0.2% solution of monoalkyphenyl ester of polyethylene glycol based on a polymer distillate and 10 ml water, followed by heating on a water bath at temperature of 80-98°C for 10-15 minutes.
EFFECT: high sensitivity of analysis.
5 dwg, 1 ex
FIELD: analytical methods.
SUBSTANCE: group of inventions is directed on detecting and quantitatively determining hydrogen radicals present in water or in aqueous solution and is characterized by adding sodium 3,5-dibromo-4-nitrosobenzenesulfonate to sample to detect hydrogen radicals from coloration appearing as a result of their absorption characteristics, and additionally characterized by blowing gaseous hydrogen through 1,1-diphenyl-2-picrylhydrazide solution absorbing near 517 nm and sodium 3,5-dibromo-4-nitrosobenzenesulfonate solution at constant velocity in presence of platinum black in order to quantitatively evaluate hydrogen radical concentration using calibration curve based on correlation between coefficient of absorption near 450 nm for azo compound of sodium 3,5-dibromo-4-nitrosobenzenesulfonate and concentration of hydrogen radicals appeared.
EFFECT: increased determination accuracy and enabled analysis of hydrogen radicals in various media.
6 cl, 15 dwg, 1 tbl, 5 ex