Method of chromatographic identification of components of complex mixtures of organic compounds
(57) Abstract:Usage: in gas chromatography to determine the qualitative composition of multicomponent mixtures of organic compounds. The inventive method comprises passing an identifiable substance through a system of series-connected columns filled with different sorbent polarity, sampling after each column, getting the spectrum holding in the first non-destructive detector, the transmission of the sample at the second detector of a different type, the calculation according to the data from two detectors of the sensitivity coefficient and the relative retention and identification of the substance on the obtained values. On the second detector, the input connected to the output of the first detector, transmit sequentially samples from the first detector and shoot range of retention on the second detector. Sensitivity factor is chosen as the average value of the ratio of the areas of the corresponding peaks in the two spectra retention. table 1. The invention relates to gas chromatography and can be used to determine the qualitative composition of multicomponent mixtures of organic compounds.The known method DLNA United columns and remove chromatographic spectrum of the substance, which in this case is a set of relative values of retention, calculated by the given values of retention, and the combination of chromatographic peaks associated with a given substance. In this way it is possible to conduct both group and individual identification of substances through the spectrum and the set of relative valuesicharacteristic only for this matter. But very often the set of relative valuesifor different substances is close to its values. In this case, identification is difficult and requires additional criteria for the final classification of the substance to a particular class of compounds. Closest to the claimed method is a method for the identification of components of complex mixtures using chromatographic spectra, in which the identifiable substance is introduced into the system serially connected columns Packed with sorbents of different polarity, each of which has an output of first detector through the micro capillary and the detector signals are recorded as a spectrum of a substance that contains a number of peaks corresponding to the number of columns used. Next, the sample gets wholly in bufferno peak on the chromatogram. Next, calculate the retention indices of the analyte in each column, then determine the sensitivity coefficients. On the basis of data obtained by determining the retention indices of the coefficient of relative sensitivity of the two detectors, conduct identification by comparing the received data with reference 
The disadvantage of this method is that because of the dependence relationship of the signals of the two detectors (ratio of peak areas) from a ratio of the flow of carrier gas is difficult to obtain reliable information on the matter.The technical result of the invention is the provision of reliability and accuracy of the information.This is due to the fact that in the method of chromatographic identification of components of complex mixtures of organic compounds identifiable substance is passed through a system of series-connected columns Packed with sorbents of different polarity, and after each column divert part of the flow to the first (non-destructive) to the detector, on the chromatogram register first range of substances consisting of consecutive peaks, the number of which corresponds to the number ipeiroy second range of the same substance. For any spectrum calculated relative value of holding
which shows the retention time of the component in a separate column
n number of columns.,
where i is the column number
retention time on the i-column
retention time on i-1 column.The coefficient of relative sensitivity (Cotn) is defined as the average value of the corresponding coefficients calculated by the ratio of the areas of the corresponding peaks in the spectra obtained at different detectors.Using a combination of iand KRelenables high accuracy and in a shorter time to conduct both group and individual registration.Examples of specific implementation method.Chromatographic spectra get five columns, made of stainless steel tube (length 2 m, internal diameter 2 mm). As stationary phases were used: Apiezon L, cryptochrome-methylsilicone oil (QF-1), pentagonally ether (PE), polyethylene glycol (mol. mass 20M (PET-20M), 1,2,3-Tris (cyanoethoxy)propane, applied to chromaton N-AW, graining 0,12 0,16 mm at 10 to 15% wt. The flow of carrier gas of nitrogen in sistemaren microcapillary. The signals of the detectors are recorded in the form of two spectra of substances consisting each of five peaks. Since the sensitivity of the detectors to various substances, the peak areas of the same substance, registered a flame ionization detector and katharometer different.As an example, for identification were used, for example, two pairs of solutes: ethylbenzene hexane, o-xylene-heptane, which was introduced into the system. After passing each substance of the whole system, it turns out two of the chromatogram with the range I and range II, each of which consists of five peaks. By the values of the retention was calculated values of ri. The set of valuesicharacteristic only for these substances. However, a comparison of valuesiethylbenzene with valuesihexane shows that these values are very close. The calculation Cot (based on peak areas) shows that the values of Cot for hexane and ethylbenzene differ significantly: for Paksane Cotn=0,93, for ethylbenzene Cotn=1,32, for o-xylene Cotn= 0,98, and heptane, Cot=1,14. The measurement results are summarized in table 1.Thus, the use of Corn along with setiallows control group and individualistic compounds, including the transmission of identifiable substance through a system of series-connected fibres filled with sorbents of different polarity, the sampling after each column, getting the spectrum holding in the first non-destructive detector, the transmission of the sample at the second detector of a different type, the calculation according to the data from two detectors of the sensitivity coefficient and the relative retention, identification of the substance on the received values, wherein the second detector, the input connected to the output of the first transmit sequentially samples from the first detector, remove a range of retention at the second detector and the sensitivity coefficient is chosen as the average value of the ratio of the areas of the corresponding peaks in the two spectra retention.
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
SUBSTANCE: system for gas-chromatographic analysis of air samples has two chromatographs 1 with plasma ionisation detectors 2, a chromatograph 4 with a heat conductivity detector 5, chromatographic packed columns 12 filled with an adsorbent, concentrators 13 installed in chromatographs 1 and 4. The system also includes an information conversion device 14 connected to a computer 15, having special software. The system also includes a device 8 for obtaining deionised water, a hydrogen generator 9, three gas preparation units 10 with three control panels 11, two electrometer amplifiers 3 and detector power supply 6. The device 8 for obtaining water is connected to the hydrogen generator 9 which is connected to each gas preparation unit 10 of chromatographs 1 with plasma ionisation detectors 2 through the control panel for feeding hydrogen 16, and to the detector power supply 6, connected to the chromatograph 4 with the heat-conductivity detector 5, and the two electrometer amplifiers 3, connected to two chromatographs 1 with plasma ionisation detectors 2, are connected to connecting cables from control panels 11 and the information conversion device 14.
EFFECT: providing quality and accurate estimation of content of hazardous impurities and concentration thereof in air samples, improved operational qualities of the system.