The method of determination of paraffin hydrocarbons in-olefins
(57) Abstract:The method is designed to determine paraffin hydrocarbons in the olefin. The inventive method involves dilution of the sample heptane in a volume ratio of the sample : heptane equal to (1-1,2):5, passing the sample through chemical sorbent fractions of 0.06 to 0.1 mm at a volume ratio test : chemical sorbent equal to 1:(45-50), collecting the first portion of the eluate, drying to constant weight, and determination of the mass balance. As the use of chemical sorbent silica gel, treated with silver nitrate. The volume of the first portion of the eluate is not less than 2.5 times the size of the volume of solution taken for the chromatography was carried out. The invention relates to the field of analytical chemistry, namely the chromatic method of determination of paraffin hydrocarbons in the olefin fraction C20-26.There is a method of determining the paraffin hydrocarbons in the olefin fraction C20-26 by subtracting from 100% the content of olefins, a specific method synthesized.The disadvantage of this method is high (up to 100 Rel.%) the measurement error that is associated with low paraffin content (about 5 wt.%) compared with the content of the result is a method of determining the paraffin-olefin fraction C16-18 by separating paraffins from olefins by liquid chromatography, according to which 2 g of the analyzed sample is mixed 0,03-0,04 g pentadecane ("label"), then 1 g of the sample with the "label" is served on top of a column containing 20 g of sorbent AgNO3/SiO2with faction 0,06-0,16 mm Paraffin hydrocarbons elute with hexane, the eluate containing the label, and contained in the sample paraffins analyzed by gas chromatography.The disadvantages of the method are its high cost associated with a high consumption of silver nitrate (2,22 g on one definition), high uncertainty associated with the complexity contained paraffins (20 species), when the error in the determination of each component contributes to the definition of the total content of paraffin hydrocarbons, as well as the unacceptability for more analysis of high molecular weight olefins (C20-26) solidifying at room conditions.The essence of the invention is a method for the determination of paraffin hydrocarbons in the olefin, in which the sample is diluted with heptane in a volume ratio of the sample: heptane (1-1,2):5 (to ensure the temperature of solution turbidity not exceeding 20oC) and injected into a column with a diameter of 10 the next volume ratio of the sample olefins:chemical sorbent 1: (45-50), elute with heptane until the volume of the eluate consisting of not less than 2.5 times the volume of the aliquot (solution of the sample introduced into the column), the eluent is evaporated, and determine the mass balance.Dilution of the sample heptane to provide the cloud point of the solution not exceeding 20oC allows to avoid overstatement of the results of determination by eliminating overshoot undissolved olefins, and the use of the silica gel fractions of 0.06 to 0.1 mm allows to reduce the consumption of chemical sorbent containing silver nitrate, and also to facilitate its preparation (to carry out the drying at atmospheric pressure).Determination of paraffin hydrocarbons in the olefin by dilution with heptane in a volume ratio of the sample:heptane (1-1,2):5 and passing through a column with a diameter of 10-11 mm, filled with silica gel fractions of 0.06 to 0.1 mm, treated with nitrate of silver, with a volumetric ratio test of olefins: chemical sorbent 1: (45-50), elution with heptane to achieve the volume of eluent consisting of not less than 2.5 times the volume entered in the column of solution samples, is a distinguishing characteristic, not found in similar technical solutions allows to reduce the error to define the characteristics and the achieved effect confirms the compliance of the proposed technical solution criteria invention of "novelty" and "inventive step".The simplicity of the analysis, the availability, accuracy, the ability to implement on an industrial scale confirm compliance with a criterion of "industrial applicability".The invention is carried out as follows. 1 g of sample was diluted with 5 cm3heptane, stirred until complete disappearance of turbidity, 1.4 to 1.5 g of the obtained solution contribute in column 7 g of chemical sorbent, representing the silica gel fractions of 0.06 to 0.1 mm, treated with a solution of silver nitrate (15 g of salt dissolved in 50 cm3water, put on 135 g of silica gel and dried for 15 hours at a temperature of 120-125oC and atmospheric pressure, or 7 hours at a temperature of 105oC and a residual pressure of 50 mm RT.cent.), paraffins elute with heptane until the volume of the eluate 5 cm3in suspended tube, the eluate blow a current of air at room temperature, the residue is dried at 105oC for 1 h and weighed. The difference of the masses determine the mass of paraffin hydrocarbons.Mass fraction of paraffin hydrocarbons are calculated according to the formula
< / BR>where
X - mass fraction of paraffin hydrocarbons in wt.%;
m is the mass selected paraffins, g;
M1is the mass of the original sample taken for analysis, g;
M2A sample of olefins is heated in a water bath with a temperature of 50-70oC to obtain a transparent mass, make a 1 cm3samples suspended in Erlenmeyer flask 50 cm3and again weighed. The difference of the masses determine the mass of a sample (0,9172 g). Poured 5 cm3heptane and thoroughly stirred to obtain a clear solution. Into the flask insert a cork inserted in her pipette with a capacity of 2 cm3and weighed. Selected 2 cm3solution and applied to a column with chemical sorbent dropwise. The flask with a pipette and the remaining solution is still being weighed. The difference of the masses determine the mass introduced into the column in solution (1,4265 g). After soaked made solution sample, in column contribute heptane portions, so that the height of the layer of heptane over the sorbent was 0.5 to 2.0, see the Eluate is collected in a weighed glass tube with a diameter of 1.5-2.0 cm labeled 5 cm3. Upon reaching the volume of the eluate 5 cm3tube with eluate put under current cleaned from mechanical impurities of nitrogen or air and evaporate heptane. Tube with the remainder placed in an oven with a temperature of 105oC and continue drying for 60 minutes Then cooled tube and weighed. The difference of the masses determine the Mac is Rabinovich hydrocarbons in the olefin by liquid chromatography was carried out using as the chemical sorbent silica gel, processed silver nitrate, characterized in that the analyzed sample is diluted with heptane in a volume ratio of the sample : heptane equal to (1 - 1,2) : 5, is passed through a chemical sorbent fractions of 0.06 to 0.1 mm at a volume ratio test : chemical sorbent equal to 1 : 45 - 50, the first portion of the eluate volume, constituting not less than 2.5 times the size of the volume of solution samples taken from the chromatography was carried out, dried to constant mass and determine the mass balance.
FIELD: chemical engineering; medical engineering.
SUBSTANCE: method involves plotting two chromatograms one of which is based on radioactivity (No 1) and the other one on ultraviolet absorption (No 2) or on radioactivity (No 1) and on fluorescence (No 2) and chromatogram specific relative to ultraviolet absorption (No 3) or relative to fluorescence (No 3). Material quality is estimated to be the more high the more close studied labeled compound peak shape is to trapezoid shape on the third chromatogram.
EFFECT: high accuracy of the method.
FIELD: analytical chemistry, ecology, in particular controlling of environmental air.
SUBSTANCE: claimed method includes aspiration if air sample through chemosorbtive medium, elution of formed dimethylamine salt, eluate closure with alkali, and gas chromatography analysis of gas phase with flame-ionization detection. Dimethylamine salt elution from adsorbent is carried out with 1 cm3 of distillated water; closured with alkali eluate is held in thermostat for 5 min; and as filling in separating chromatography column chromosorb 103, containing 5 % of PEG-20000 and treated with 20 % hexamethyldisilazane solution is used.
EFFECT: method for dimethylamine detection with improved sensibility and accuracy.
FIELD: chemical industry.
SUBSTANCE: during process of taking sample from technological pipe-line, absorption of water vapors and nitrogen oxides (II) and (IV) are conducted simultaneously. For the purpose the chemical agents are used which don't absorb nitrogen oxide and don't react with it. Chromatographic measurement of volume fraction of nitrogen oxide (I) is carried out by means of industrial chromatograph having heat-conductance detector by using column of thickness of 5 m and diameter of 3 mm. The column is filled with polysorbent; temperature of column's thermostat is 20-30 C and temperature of evaporator is 100C. Hydrogen is used as a gas-carrier. Concentrations of nitrogen oxide, measured by the method, belong to range of 0, 05-0, 50% of volume fraction. Method excludes aggressive affect of corrosion-active components on sensitive parts of chromatograph. Method can be used under industrial conditions for revealing factors influencing process of forming of nitrogen oxide at the stage of catalytic oxidation of ammonia and searching for optimal conditions for minimizing effluent of ammonia into atmosphere.
EFFECT: high reproduction; simplification; improved efficiency of operation.
FIELD: oil and gas production.
SUBSTANCE: aim of invention is estimating expectations for oil and gas of oil-source rock areas. For that aim, sampled rock is treated to isolate organic substance soluble in organic solvents, after which organic substance is chromatographed to detect 4-methyldibenzothiophene and 1-methyldibenzothiophene. When ratio of 4- to 1-isomer exceeds 0.9 rock is regarded as ripened.
EFFECT: increased determination reliability and rapidity.
SUBSTANCE: in the method, hard carrier with system of narrow pores and channels is kept under temperature below height of potential barriers for movement of at least one type of separated molecules.
EFFECT: higher efficiency.
FIELD: investigating or analyzing materials.
SUBSTANCE: gas analyzer comprises chromatographic columns, detectors, unit for preparing air mounted inside the thermostat, unit for control and processing signals, member for sampling, switches of gas flows, pump for pumping gas mixture, and separating passages connected in parallel and provided with the check valve interposed between them. Each of the separating passages is made of absorbing and separating chromatographic columns connected in series, and the pump is connected to the input of the gas line through the electric valve. The gas analyzer can be made of two separating passages and low pressure chromatographic columns.
EFFECT: enhanced quality of analyzing.
2 cl, 1 dwg, 1 ex
FIELD: analytical methods.
SUBSTANCE: to determine methyl alcohol in water, sample to be assayed is preliminarily subjected to distillation with sulfuric acid added in amount required to provide its concentration in mixture to be distilled c(1/2 H2SO4) = 0.002 M, while strippings constitute 6-7% of the volume of sample. Stripped liquid is thrice rinsed with hexane or Nefras at 1:1 hexane (Nefras)-to-strippings ratio. Rinsed material is then introduced into packed column filled with diatomite modified with 1,2,3-tris(β-cyanoethoxy)propane having deposited fixed phase thereon, which phase is prepared by way of consecutively keeping glycerol each time for 4 h at ambient temperature, 100°C, 130°C, 160°C, and 200°C, and then for 8 h at 230°C and for 40 h at 200°C under nitrogen bubbling conditions. Calculation of methanol content is performed taking into consideration calibrating coefficient.
EFFECT: enabled determination of small concentrations of methyl alcohol in water with sufficient selectivity and reliability.
2 cl, 2 tbl, 6 ex
FIELD: analytical chemistry.
SUBSTANCE: invention relates to method for quantitative determination of thiotriazoline and pyracetam in complex drugs by high performance chromatography, wherein silicagel with grafted 3-(chlorodimethyl)-propyl-N-dodecylcarbamate having particle size of 5 mum is used as sorbent; and degassed 0.05 M aqueous solution of potassium dihydrophosphate is used as mobile phase. Mobile phase velocity is 1 ml/min, and column temperature is 30°C. Method of present invention makes it possible to determine content of two abovementioned active ingredients simultaneously.
EFFECT: simplified process of sample preparation.
3 ex, 3 tbl
FIELD: biotechnology, in particular content determination of polymer chitosan molecules, chitosan-chitine polymer molecules and molecules of chitosan-protein complex in finished form of chitosan.
SUBSTANCE: claimed method includes application of high performance chromatography column filled with polyvinylbenzene sorbent with refractometer detector. As eluent and for dissolving of chitosan preparation samples acetic acid aqueous solution is used. Chain-length distribution is determined on the base of first chromatography peak, and polymer molecular content is calculated on the base of area of first, second and third chromatography peaks, divided up to zero line and belonging to polymer chitosan molecules, chitosan-chitine polymer molecules and molecules of chitosan-protein complex, respectively. To calculate chain-length distribution of polymer chitosan molecules separately calibration curve is plotted using dextran polymer standards.
EFFECT: new effective method for determination of polymer chitosan molecules in chitosan preparations.
4 cl, 3 dwg
FIELD: the invention refers to laboratory chromatographic devices for conducting high-speed chromatographic analysis.
SUBSTANCE: the express-chromatron has an injector, a chromatographic column located in a thermostat, a detector, an amplifier of the signal of the detector, an analog-digital converter, a control system, a pneumatic system. The column is fulfilled either in the shape of a short capillary column or either in the shape of a polycapillary column. The injector is fulfilled with possibility of introduction of the test for the time of 5-50 ms. The detector and the amplifier of its signal are fulfilled with possibility of ensuring constant time of no worse then 10-3 sec. The analog-digital converter is fulfilled with possibility of ensuring speed of no less then 200 measurements in a second.
EFFECT: ensures conducting high-speed chromatographic analysis.
11 cl, 2 dwg