Method of determining content of monomethylaniline in hydrocarbon fuels using indicator testing means and indicator testing means therefor

FIELD: chemistry.

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

 

Group of inventions relates to the field of study of hydrocarbon fuels according to the normalized quality indicators and can be used for the determination of N-methylaniline in a variety of hydrocarbon fuels, in particular synthetic, in oil products, such as, for example, automotive gasoline, diesel fuel and other and other fuels of the hydrocarbon composition.

Currently N-methylaniline (monomethylaniline) is an effective anti-knock additive to gasoline, allowing significant improvement in the octane number. However, this substance has a number of negative properties: inhibits the combustion of fuel, resulting in lower efficiency of the engine, causes deposits in the engine and the wear of the cylinder group, and increases the toxicity of exhaust gases. For these reasons, the content of N-methylaniline in fuels is tightly regulated by the technical regulations of the Customs Union "About requirements to automobile and aviation gasoline, diesel and ship fuel, fuel for jet engines and fuel oil" (approved October 18, 2011 No. 826), according to which the use of aromatic amines (N-methylaniline) in motor gasoline is prohibited on the territory of the Republic of Belarus and in the Russian Fe�erachi their content must not exceed 1,0% by volume. for 3 and 4 grades of fuel, the issue and circulation of which terminates December 31, 2015 in connection with a complete transition to diesel environmental class 5. Demand for motor gasoline (AB), N-methylaniline may not be used in the fuel of environmental class 5. The latter is due to the need to control its content. Diesel fuel and other petroleum products may also contain N-methylaniline, which hits them in the process of refining.

Known methods for determination of N-methylaniline in motor gasoline, according to which the content of N-methylaniline define methods based on chromatography ("Chromatographic method for the determination of monomethylaniline technical in motor gasoline", Moscow, 2010, the FAA 25th state research Institute of applied chemistry of the Ministry of defense of Russia" (one HUNDRED 08151164-015-2010); Method of gas chromatographic analysis of motor gasoline "Chemistry and technology of fuels and oils", 2001, №4, pp. 44-48; GOST R 54323-2011 "the Gasoline. Determination of N-methylaniline by the method of capillary gas chromatography").

The disadvantages of these methods are the complexity of the analysis, the need to use expensive equipment and consumables, as well as limiting the use of these methods in the field of sampling, for example directly on �CS.

Known method for the qualitative and quantitative determination of monomethylaniline in automotive gasoline by a change in color of the indicator after contacting it with sample to be analyzed gasoline (EN 2425366, 2011). At the same time as the indicator is used in the ratio of 1:1 water / ethanol solution with a concentration of 0.15-0.25 wt.% Bromphenol blue. The specified solution is impregnated solid support, incubated at room temperature until dry. Prior to contacting with the sample to be analyzed gasoline impregnated with a solution of indicator solid support immersed in a solution of 0.01-0.02 mol/DM3hydrochloric acid until the yellow color, and after contacting impregnated with a solution of indicator solid carrier with the sample of the analyzed gasoline in the identification of colors from yellow through green to violet-blue judged on the presence of monomethylaniline, the quantitative content of which is determined by the graded color scale. Solid support coated with indicator keep light in the form of strips of size 10×100 mm. as the solid carrier used filter paper or filters obezdolennye with a pore diameter of 1-10 microns.

The disadvantages of the described method are not sufficiently high sensitivity in determining the content of monomethyl�Ileana in hydrocarbon fuels, the need for additional training of strips impregnated with an indicator before using them, as well as the need to use aggressive chemical reagent hydrochloric acid solution.

Closest to the described group of inventions are a method of determination of N-methylaniline in hydrocarbon fuels - automotive gasoline - test indicator means according to the color change after the contacting with the sample to be analyzed gasoline and indicator test tool for its implementation, described in patent RU 2489715, 2013. Thus as an indicator use 4-methoxybenzothiazole tetrafluoroborate deposited on a solid basis. As an indicator of test tools used or reagent indicator paper as the solid fundamentals of vehicle which uses a paper for rapid tests or indicator tube, as the solid foundations of filler which is used as a silica. In the first case, the content of N-methylaniline is determined by the discoloration of the paper from white to pink, light red, to dark red or Burgundy color. When using the indicator tube, the content of N-methylaniline is determined by the length of the painted dark-red zone of the tube.

Used 4-methoxyphenylacetone tetrafluoropropylene synthesized by mixing a solution of hydrochloric acid, 4-methoxyaniline and an aqueous solution of sodium nitrite reagents, followed by separation and drying of the precipitated sludge. From reagent indicator paper, treated by impregnating with an aqueous solution of 4-methoxyphenylacetone of tetrafluoroborate with the addition of oxalic acid, prepare test strips and indicator sorbent - oxide of silicon is placed in a glass tube with a constriction, the length of the column filler of 90 mm. the Concentration of N-methylaniline in gasoline is determined by the color change of the indicator paper after contact with the sample fuel and comparing the result with the calibration color chart. The range defined by this indicator test concentrations of N-methylaniline is 0.1 to 2.0%.

The disadvantage of this method of determining the content of N-methylaniline in motor gasoline test indicator and indicator means test the means for its implementation is the low sensitivity. So, the impossibility of determining the concentration of N-methylaniline less than 0.1% of the known method and means causes the impossibility of achieving a reliable result of the quality control of gasoline, which, according to the requirements of environmental fuels, as well as the requirements established by the legislation of some countries, the use of N-methylaniline is strictly prohibited.

�besides the use of 4-methoxyphenylacetone of tetrafluoroborate it requires multistage preliminary obtain with the use of reagents such as 4-methoxyaniline (p-anisidine), an aqueous solution of hydrochloric acid, tetrafluoroborate ammonium, an aqueous solution of sodium nitrite reagents, and impregnating an aqueous solution of 4-methoxyphenylacetone of tetrafluoroborate further comprises oxalic acid. The latter also creates disposal problems of waste solutions containing highly toxic reagents.

Thus, the known method of determining the content of N-methylaniline in hydrocarbon fuels test indicator and indicator means test the means for its implementation is not effective enough.

The task of the group of inventions is to improve their efficiency.

The task is achieved by creation of indicator test means for the determination of N-methylaniline in hydrocarbon fuels, representing a neutral aluminum oxide with immobilized on its surface by hexacyanoferrate (III) potassium, formed in the form of tablets.

The task is achieved also by a method of determining the content of N-methylaniline in hydrocarbon fuels test indicator tool according to the color change after the contacting with the sample analizirue�CSO fuel, wherein as the indicator test tools using neutral aluminium oxide with immobilized on its surface by hexacyanoferrate (III) potassium, formed in the form of tablets.

Achieved technical result of the described group of inventions is to improve their efficiency through a more reliable determination of low concentrations of N-methylaniline in hydrocarbon fuels (the minimum detectable concentration is 0.01% by vol.) compared with the known method and a tool (the minimum detectable concentration is 0.1 vol.%).

The essence of the group of inventions is as follows.

Prepare test indicator tool. To do this, hold the immobilization of hexacyanoferrate (III) potassium on the surface of the sorbent - neutral aluminum oxide - by treating it with an aqueous solution of hexacyanoferrate (III) potassium for 20-30 min. After which the resulting sorbent is separated by filtration and dried. It is possible to use, in particular, 0,9-1,3% (wt.) the aqueous solution of hexacyanoferrate (III) potassium and to carry out the drying of the adsorbent, in particular, at a temperature of 105-115°C for 80-90 minutes. The dried sorbent is formed in the form of tablets by compression. The result is a neutral aluminum oxide with immobilized on its surface hexacyanoferrate�m (III) potassium, formed in the form of tablets. The finished tablets were stored in a container that keeps out light.

Determination of the concentration of N-methylaniline in hydrocarbon fuels using the above indicator means test is as follows.

Prepare a series of model hydrocarbon fuels containing different amounts of N-methylaniline: 0.01% vol. to 2.0%. For this fuel, not containing N-methylaniline, add a known amount of the substance, and then by dilution gain of model fuel with lower concentrations of N-methylaniline.

Conduct testing of model mixtures by coating the above-described display means neutral aluminium oxide with immobilized on its surface by hexacyanoferrate (III) potassium, formed in the form of tablets, a few drops (e.g., two) of each model compound, followed by fixation spot color on the surface of the tablet. Thus, each color spot on the tablet corresponds to the number of N-methylaniline in the fuel. The results are transferred to a paper medium and receive the graded color scale consisting of colors (from bright yellow to red-brown of varying intensity of staining corresponding to certain concentrations of N-methylaniline in the mixture model.

D�I determine the content of N-methylaniline in the tested hydrocarbon fuels on the tablet of the above-described indicating means test is applied a few drops (e.g., two) analyze fuel and capture spot color in contact with the sample. The concentration of N-methylaniline in the sample is determined by the change in color and intensity of staining spots on the tablet from bright yellow to red-brown, which compare fixed color calibration with color scale.

In this case, if the content of N-methylaniline in the studied fuel exceeds 0,01-0,03% (vol.) (depending on the fractional composition of the analyzed fuel), a spot of color on the tablet indicator means test, you receive directly after contact with the analyzed sample. In this case, the fixation spot color and its comparison with the calibration color chart is carried out directly after contact with the analyzed sample for 20-30 seconds. When the content of N-methylaniline in the studied fuels at the level of 0.01-0.03% (vol.) (depending on the fractional composition of the analyzed fuel) color stain on the tablet appears after 5-10 min. In this case, the fixation spot color and its comparison with the calibration color chart is carried out after contact with the analyzed sample within a specified time period.

The following examples illustrate the invention but do not limit its use.

Example 1

Carry out the determination of the content of N-methylaniline in commodity Ugledar�the bottom of the fuel with a boiling point up to 150°C.

For the preparation of indicator means test is carried out the immobilization of the indicator on the surface of the carrier - neutral aluminum oxide. For this purpose, 5 g of neutral aluminium oxide is placed in a conical flask, pour 1% (wt.) an aqueous solution of hexacyanoferrate (III) potassium ("Rahim", Russia) and incubated for 30 min, after which the treated adsorbent is separated by filtration, and dried at a temperature of 105-115°C for 90 minutes. The dried sorbent was subjected to pressing with a load of 5 tons with getting pills. The result is a neutral aluminum oxide with immobilized on its surface by hexacyanoferrate (III) potassium, formed in the form of tablets. The finished tablets were stored in a container that keeps out light.

Next, prepare 8 samples of model hydrocarbon fuels containing different amounts of N-methylaniline: from 2.0 to 0.01%. For this purpose, fuel is added a known amount of the substance, and then by dilution gain of model fuel with lower concentrations of N-methylaniline. Wherein the hydrocarbon fuel is used, the model of a petroleum fraction boiling in the range of up to 150°C, not containing N-methylaniline. The obtained tablets indicator means test is applied to two drops of each mixture model, followed by fixation spot color on p�surface tablets. Transfer the results on a paper medium and receive the graded color scale, consisting of 8 different colors of staining intensity, corresponding to the particular concentrations of N-methylaniline in the analyzed mixture. The results obtained when creating the calibration of the color scale shown in the table.

For the determination of N-methylaniline in the tested commercial hydrocarbon fuel having a boiling point up to 150°C per tablet derived indicator means test is applied two drops of fuel and record the color of the stain at the site of contact. The concentration of N-methylaniline in the sample is determined by the change in color and intensity of staining spots on the tablet from bright yellow to red-brown, which compare fixed color calibration with color scale (example 1 in the table). In this example, the color patches on the tablet used indicator means test after application of fuel samples submitted for analysis, has bright yellow-green color that corresponds to the content in the fuel of N-methylaniline 0,06% vol.

Example 2

Carry out the determination of the content of N-methylaniline in commercial hydrocarbon fuels boiling in the range from 150 to 356°C.

Cooking indicator means test carried out analogously to example 1. 5 g of neutral �of ksid aluminum is placed in a conical flask, pour 1.2% (wt.) an aqueous solution of hexacyanoferrate (III) potassium ("Rahim", Russia) and incubated for 20 min, after which the adsorbent is separated by filtration, and dried at a temperature of 105-115°C for 80 minutes. The dried sorbent was subjected to pressing with obtaining tablets. The result is a neutral aluminum oxide with immobilized on its surface by hexacyanoferrate (III) potassium, formed in the form of tablets. The finished tablets were stored in a container that keeps out light.

Next, get the graded color scale, analogously to example 1, except that a hydrocarbon fuel is used, the fraction boiling in the range of 150 to 356°C, not containing N-methylaniline. The results obtained when creating the calibration of the color scale shown in the table.

For the determination of N-methylaniline in the tested commercial hydrocarbon fuels boiling in the range from 150 to 356°C, the tablets obtained indicator means test is applied two drops of fuel tests and record the color of the stain in contact with the sample. The concentration of N-methylaniline in the sample is determined by the change in color and intensity of staining spots on the tablet, which compare fixed color calibration with color chart (example 2 in the table).

In this testing C�em spot on the tablet used test indicator means after application of the sample fuel, submitted for analysis, has a pale blue color, which corresponds to the content of N-methylaniline 0,01% vol. (example 2 in the table).

Entered the content of N-methylaniline in fraction, % (vol.)Color-treated test when testing hydrocarbon fractions
Example 1Example 2
Fraction boils up to 150°CFraction boils between 150 to 356°C
NoBright yellowOrange-yellow
2,0Red-brownRed-brown
1,0Dark brownDark brown
0,5BrownBrown
0,25Light brownLight brown
0,06Bright yellow-greenYellow-green
0,03Pale yellow-greenBlue
0,01Pale bluePale blue

Thus, the described method of determining the content of N-methylaniline in hydrocarbon fuels indicator test means and test indicator tool allow to achieve a more reliable determination of low concentrations of N-methylaniline in hydrocarbon fuels compared with the known method and means.

1. Indicator test means for the determination of N-methylaniline in hydrocarbon fuels, representing a neutral aluminum oxide with immobilized on its surface by hexacyanoferrate(III) potassium, formed in the form of tablets.

2. Method of determining the content of N-methylaniline in hydrocarbon fuels test indicator tool according to the color change after the contacting with the sample to be analyzed fuel, and as a tracer test means use the tool according to claim 1.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention can be applied for the estimation of a washing ability of petrol and diesel fuel and influence of their washing abilities on technical-economic and ecological (TE) characteristics of an engine (E). The method consists in the preliminarily "pollution" of E with an etalon pollution mixture (EPM) of fuel and oil, which ensures its working in a fixed mode. Upon use of 20-40 l EPM the E is stopped, cooled, dissembled and pollutions (P) are registered. Then E works on the test fuel at standard modes (SM). Its TE characteristics are measured. Then P is registered again. Parameters of SM are given.

EFFECT: increased degree of reliability and objectivity of determining the washing ability of petrol and diesel fuel.

9 cl, 4 tbl

FIELD: oil-and-gas industry.

SUBSTANCE: hydrocarbons concentration is measured in vapour-air mix flowing from filler neck as well as time interval from fill in start to initial occurrence of hydrocarbons in said mix, said concentration being taken as the minimum magnitude. Time interval when hydrocarbons concentration reaches maximum magnitude and moment when maximum level in the tank is reached are measured. Bulk of losses of oil or oil products is determined by the formula: M"пп"=V"ц"[(t"ц"tCmax)Cmaxt"ц"+(tCmaxtCmin)(Cmax+Cmin)2tCmax], where M"пп" is bulk of losses caused by evaporation in vapour-air mix emissions, kg; V"ц" is tank volume, m3; t"ц" is time interval from fill in start to maximum fill in level, min; Cmax is maximum concentration of hydrocarbons in said mix, kg/m3; Cmin is minimum concentration of hydrocarbons in said mix, kg/m3; tCmax is time interval from fill in start to occurrence of vapours with concentration Cmax, min; tCmin is time interval from fill in start to occurrence of vapour with concentration Cmin, min.

EFFECT: lower labour input, higher accuracy of loss determination.

1 tbl

FIELD: chemistry.

SUBSTANCE: dispersion-indicator composition is prepared, for which purpose hydrochloric acid and water-alcohol solution of bromophenol blue are introduced into distilled water, obtained composition is combined with petrol sample, into which methyl-tert-butyl ether is preliminarily added, mixture is mixed and settled at room temperature, volume of foamy layer of blue-light blue colour is measured at the boundary of “petrol-water" separation, and if its value is not less than 1 cm3 conclusion about detergent additive in petrol is made.

EFFECT: acceleration of identification with high degree of its reliability.

1 ex, 5 tbl

FIELD: chemistry.

SUBSTANCE: method of evaluating corrosiveness of jet fuel comprises determining the decrease in weight of copper-containing material placed in the fuel before and after testing at high temperature. The copper-containing material used is copper foil which is placed in the fuel and held in hermetically sealed cells in the form of metal vessels at temperature of 150±2°C for 4 hours while holding in two steps of 2 hours each and replacing the fuel after the first step. The greater the decrease in the weight of the copper foil before and after test, the more corrosive the jet fuel.

EFFECT: high reliability and faster evaluation.

1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to chemical methods of expertise of explosive substances and forensic identifying preparations. A method of marking an explosive substance consists in the introduction of a marking composition, containing identifiers, the quantity of which equals the quantity of technical parameters to be marked, into the explosive substance, obtained by mixing of separate components. To mark the explosive substance each separate component, included into the mixture of the explosive substance, is marked. The marking composition for each separate component is composed of at least one polymer material from the group of polyorganosiloxanes with the length of a molecular chain, representing an identifier, different from lengths of molecular chains and values of viscosity of polymer materials in the marking compositions of other separate components, constituting the mixture of the explosive substance. As the marking composition of the explosive substance a set of marking compositions of separate components of the said substance mixture is used.

EFFECT: improvement of marking.

3 cl, 3 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: method includes determination of the density at the fuel temperature 20°C, determination of the averaged boiling temperature Tc, °C, by calculated dependences on temperatures of boiling away of different fuel fractions, setting the density range at 20°C from 700 to 1020 kg/m3, determination of kinematic viscosity at a temperature of 50°C with the fuel density from 860 to 1020 kg/m3 and the temperature of boiling away of final fuel fraction higher than 400°C, equipping a nomogram for CI estimation with an additional scale of viscosity, matched with the Tc scale on the section from 268 to 320°C, setting the Te range from 90°C to 320°C, setting the range of the kinematic viscosity scale from 2.0 to 1000 mm2/s, setting the range of cetane index scale, units, from 0 to 70. The nomogram makes it possible to determine CI of any liquid hydrocarbon fuel (from petrol to the residual one).

EFFECT: extension of assortment of analysed fuels and increased reliability of estimation.

1 dwg, 1 tbl, 4 ex

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the field of analysis of physical properties of liquids. A device contains a container for sampling with a scale with a piston and rod placed in it, software and hardware to measure time and temperature, a tube for liquid intake during sampling in order to determine the relative viscosity, a thermistor which can be installed at the tube during determination of microcone penetration, demulsifying ability and index of the liquid heating dynamics, a cone that can be installed instead of the piston on the rod by means of a threaded connection for determination of microcone penetration, a plug or a cover which can be installed into the container nipple instead of the tube for determination of microcone penetration and demulsifying ability, and a support for the container installation.

EFFECT: simplification and acceleration of the analysis as well as increase in its information content and reliability.

5 cl, 4 tbl, 10 dwg

FIELD: chemistry.

SUBSTANCE: filler used is chromogenic ion-exchange dispersed silica with covalently grafted hydrazones or formazans.

EFFECT: high sensitivity and selectivity of detecting metals.

3 tbl, 4 dwg, 14 ex

FIELD: oil and gas industry.

SUBSTANCE: at first sample of tested oil product with fixed volume is passed through water-coagulating agent placed between turns of a flat spiral mounted in a cavity of the element having shape of a truncated cone. When the sample is passed along the spiral the time for coagulation of free water microdrops in the sample is extended. Then the sample of the tested oil product is passed through a filter membrane with a deposited layer of water-sensitive chemical agent. At that by means of the hollow element having shape of a truncated cone this sample is localised at the surface of this water-sensitive chemical agent and water availability or concentration is evaluated by its colour changing. Additionally water concentration in the sample of the tested oil product is evaluated against decrease of the sample fixed volume before the water-sensitive chemical agent changes its colour.

EFFECT: improved accuracy of the analysis.

1 dwg

FIELD: engines and pumps.

SUBSTANCE: proposed method consists in application of the dependence of kerosene compatibility with rubber upon content of antioxidant therein for determination of antioxidant amount in tested kerosene. Rubber seal ring is used as the rubber specimen in proposed method. Said ring is compressed to 20% of its thickness, placed in tested kerosene to fix compression force continuously during the entire test for determination of compatibility of kerosene with rubber. Compatibility index is calculated by the formula including maximum rubber ring compression force and ring compression force after 3 hours of holding said ring in kerosene at 150°C.

EFFECT: perfected method.

3 dwg, 3 tbl, 1 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

FIELD: medicine.

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

FIELD: measurement equipment.

SUBSTANCE: invention relates to ecology, namely to sanitary-chemical control of the state of environment and can be used for solution of tasks for detection and measurement of harmful substance concentrations in the air. A device for detection of harmful substances in the air includes an air flow booster and the primary chemical transducer; with that, the air flow booster includes the following: a control unit providing setting of parameters of bleed air, operation and control of the device; an air path for transportation of an air flow; an air pump connected to the control unit for pumping of air through the air path; a self-contained power source, and the primary chemical transducer is connected to the air path. With that, the device includes flow and temperature sensors of the pumped air, which are arranged in the air path, as well as sensors of atmospheric pressure and relative humidity of the pumped air, which are arranged outside the air path, and the control unit includes an information display device; at least one control button and an electronic circuit providing the following: recording of data from sensors; determination of air density; control of volumetric flow of the pumped air; adjustment of air sampling time, and analogue-to-digital conversion of the obtained and transmitted data.

EFFECT: improving accuracy of taken air volumes; increasing quick action of operation of the device; control and fixation of parameters of the taken air (volumetric air flow rate, atmospheric pressure, temperature and humidity); increasing ease of use; improving accuracy of readout of information from the primary chemical transducer; providing technical control and fixation of colorimetric changes of the primary chemical transducer; reducing overall dimensions and the weight of the device; enlarging functional capabilities.

24 cl, 1 dwg

FIELD: chemistry.

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.

1 ex

FIELD: instrumentation.

SUBSTANCE: invention relates to the field of gases identification and refers to a spectral analysis system for gases identification using a treated tape. The system includes a treated tape, an adjustable colour source, a photodiode, a colour identification sensor and a microprocessor. The adjustable colour source emits radiation in the direction of the treated tape with multiple varied wavelengths. The photodiode measures the radiation reflected from the treated tape. The microprocessor analyses the measurement results and, proceeding from the colour identified and the colour spot intensity, identifies the type and concentration of the gas the treated tape has been exposed to. Additionally, the microprocessor, with the help of the colour identification sensor, controls the radiation wavelength of the adjustable colour source and, whenever required, corrects the colour source radiation.

EFFECT: technical effect consists in increased sensitivity and ensuring the possibility of different type gases detection.

13 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: at first sample of tested oil product with fixed volume is passed through water-coagulating agent placed between turns of a flat spiral mounted in a cavity of the element having shape of a truncated cone. When the sample is passed along the spiral the time for coagulation of free water microdrops in the sample is extended. Then the sample of the tested oil product is passed through a filter membrane with a deposited layer of water-sensitive chemical agent. At that by means of the hollow element having shape of a truncated cone this sample is localised at the surface of this water-sensitive chemical agent and water availability or concentration is evaluated by its colour changing. Additionally water concentration in the sample of the tested oil product is evaluated against decrease of the sample fixed volume before the water-sensitive chemical agent changes its colour.

EFFECT: improved accuracy of the analysis.

1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to field of analytical chemistry, namely to photocolorimetric method of analysis, and can be used for determination of iron (II) content in extract of spruce needles, containing iron (II) in very low concentration. Method includes its transfer into complex compound with organic reagent, with addition of 150-200-fold amount of organic reagent to solution of iron (II) with pH 3, as reagent used is Congo red, 0.2-0.4 ml solution of surface-active substance in form of 0.2% solution of 6-aminocapronic acid, and water to 10 ml with further heating on water bath at temperature 80-98°C for 10-15 min.

EFFECT: increased analysis sensitivity.

1 ex

FIELD: chemistry.

SUBSTANCE: invention describes a method of determining aluminium (III), which involves preparing a sorbent, an aluminium (III) solution, extracting aluminium (III) from the solution using the sorbent and conversion thereof into a complex on the surface of the sorbent, separating the sorbent from the solution, measuring luminescent intensity of the surface aluminium (III) complex and determining content of aluminium from a calibration curve. The sorbent used is silica gel which is successively modified with polyhexamethylene guanidine and 7-iodo-8-hydroxyquinoline-5-sulphonic acid, and luminescent intensity is measured at 495 nm.

EFFECT: low threshold of detecting aluminium, wider range of determined content, low consumption of the organic complexing agent.

4 ex, 2 tbl

FIELD: chemistry.

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: chemistry.

SUBSTANCE: method of determining tin (IV) in an aqueous solution involves extraction of tin (IV) ions. Extraction is carried out by adding antipyrine, sulphosalicylic acid and calcium chloride with concentration of 0.60, 0.35 and 2 mol/l, respectively, to the solution. After phase separation, morin solution is added to the extract to form a fluorescent tin and morin complex, followed by measurement of fluorescence of the obtained solution using liquid analyser Fluorat2-3M to determine concentration of tin (IV).

EFFECT: quantitative detection of tin ions and simple analysis.

1 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

Up!