Method gas chromatographic identification,'illogicality on individual index holding
(57) Abstract:Use: for analysis of non-biological materials by physical and chemical methods. Essence: in the calculation of the index holding mustard as a matter of comparison, the use of fluorinated and brominated analogues of the compound. The technical result of the invention is to improve the accuracy of the identification of the compound. The use of highly sensitive and selective detectors (flame photometric, electron capture) allows for quantitative chemical analysis of the compound in the samples of complex matrices in trace quantities. 1 C.p. f-crystals, 3 tables. The invention relates to the field of chemical analysis and physical properties of substances, particularly to the analysis of non-biological materials by physical and chemical methods.The relevance of developing a reliable and valid means of identification’-dichloromethylsilane (mustard gas) caused by the need for security when solving problems related to the storage and destruction of mustard gas, less resource and monetary costs, increasing detection sensitivity, and simplicity and accessibility of this method.Limestone is using as standards homologous series of n-alkanes (E. Leibnitz, H., Struppe. Guide to gas chromatography. - M.: Mir, 1988. T. 1. - S. 479). The choice of this number is most natural, as n-alkanes represent "zero structure, based on which you can reproduce the structure of all organic substances. A new parameter Kovacs called the "retention index" (PS).Along with the indisputable advantages of the system of indexes Kovacs has also some drawbacks. These include the fact that n-alkanes are not always the most convenient substances comparison due to the difference between the prevailing types of interaction with the stationary liquid phase (page) of n-alkanes and the analyzed substances. This fact significantly affects the chromatographic characteristics of time and the amount of holding in the application page of different polarity, which leads to a large range of values Yiwu the same analyte. In addition, the use of published Yiwu difficult mainly due to interlaboratory differences in the reproducibility of their definition. These differences are due to both the imprecision of the reproduction and maintenance of the apparatus parameters of the chromatographic system and mcnie separating system.The present invention is to develop a method of identifying the mustard on retention index calculated using the reference grid substances comparisons, which use it fluorinated and brominated analogues.The solution of this problem is achieved by the fact that, by analogy with the system Yiwu Kovacs identification is comprised of two substances comparison with the time in the chromatographic column immediately before and after the analyte.where z is the analogue of mustard gas emerging from the column to the mustard, z+1 - similar to mustard gas emerging from the column after the mustard.Data are expressed in logarithmic scale. By analogy with n-paraffins index of each subsequent member of a number of analogues differs for every 100 units of index (E. I.). Thus obtained numerical characteristics parameter retention was given the name of the individual retention index (IST).In table. 1-2 comparative characteristics Yiwu, IST mustard for similar and different in the polarity of the page.From the data presented in table. 1, it follows that the magnitude of Yiwu Kovacs, obtained using a number of the nutrient value in the range of 10-15 E. I., the same thing happens with the values of IST. Comparing data values Yiwu Kovacs, IST shown in the table. 2, a strong correlation of changes in index values from increasing the polarity of the page, however, the change ranges Yiwu Kovacs, IST differ significantly, for changing the first value of more than 700 E. I., and for the IST not more than 2 E. I.Health check of the proposed method for the identification of the compound was carried out in the laboratory on analytical equipment produced by Hewlett Packard, USA in the composition of the gas chromatograph HP 5890, an autosampler HP 7673 and automatic data processing systems computer-based Vectra 48/33VL.As substances "interfering impurities" present in the samples analyzed samples of complex matrices, such as soil, air, industrial zones or natural, purified water, and complicating the identification of mustard proposed substances, which are degradation products of mustard gas, which has a similar chemical structure containing sulfur atoms and halogen, and substances with similar physical-chemical properties such as boiling point and molecular mass.For example, these substances were compared changes the index of the parameters was investigated on several page with different polarity. The results of the study are presented in table. 3.From the data presented in table.3, it follows that the value of the IST obtained when using multiple page, mustard practically unchanged (less than 1 E. I.), while for substances taken as "interfering impurities, IST varies very considerably, for example, thiodiglycol 7 E. I., 1,4-dithiane 15 E. I. and so on, the results indicate the feasibility of applying the proposed method for reliable identification of the compound.It should be noted that the use of substances comparison mustard analogues allows its identification by gas chromatography using a highly sensitive, selective detectors (flame photometric, electron capture), which significantly increases the selectivity of the proposed method for the identification and reduction of determining the minimum detected quantity of the compound found in trace quantities in samples of complex matrices. 1. Method gas chromatographic identification of dichloromethylsilane (mustard gas), based on the definition of index holding, characterized in that to the and mustard.2. The method according to p. 1, characterized in that allows identification of the compound with the use of selective, highly sensitive detectors - flame photometric or electronegative.
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