The method of determination of isomers of 3-phenoxy-lebenshilfe ester 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1 - carboxylic acid
(57) Abstract:The method of determination of isomers of 3-phenoxy--Lebenshilfe ester 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylic acid by high performance liquid chromatography. As stationary phase used sorbent is silica-based. As eluent a mixture of hexane with tetrahydrofuran or ethyl acetate at a volume ratio of 100 : 0.1 to 0.6. The technical result of the claimed invention is expressed in the creation of a more effective way of determining the isomers 3-phenoxy--Lebenshilfe ester 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylic acid. The invention relates to analytical chemistry, namely, to methods for determination of isomers of 3-phenoxy--cyclopentolate ester 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cypermethrin) by high performance liquid chromatography (HPLC). The invention can be used in analytical laboratories.Cypermethrin refers to PYRETHROID insecticides and is a mixture of CIS - and TRANS-isomers. Molecule cypermethrin has three centers of asymmetry, each of which are formed (R)- and (S)-isomers, i.e. forms/BR> 3) /IR/R + /IS/S;
4) /IR/S + /IS/R.(Pyrethroids. Chemical-technological aspects./Ed. by C. K. Romanenkova. - M.: Chemistry, 1992, pp. 264-266).Since the biological activity of individual isomers of cypermethrin differ from each other, it is important to know the content of cypermethrin.In particular, for practical purposes in the production of cypermethrin is important to know the content of 4 diastereomers without separation of individual enantiomers. For example, certain drugs on the basis of cypermethrin is a mixture of the second and fourth enantiomeric pairs with the highest biological activity, while the first and third enantiomeric pairs contained in the preparations as impurities.Known methods of determination of isomeric compounds by HPLC. So, there is a method of quantitative determination of ortho-, para-, metasomal nitrobenzoic acid. As stationary phase using sorbent separon C18or silsor C18as eluent using an aqueous solution of sodium hydrogen phosphate when its concentration in eluent 0.3 to 1.5 wt.% (ed. St. USSR N 1656477).There is also known a method of determining geometric (SYN-anti) isomers of 2-(2-amino-out sorbent silsor C8or C18as the mobile phase using water containing organic modifier acetonitrile or ethanol in the amount of 11-33%. (AB. St. USSR N 1589205).It should be noted that the choice of adsorbent, eluting solvent mixtures and ratios in liquid chromatography and, in particular HPLC, is not obvious. Chromatographic separation can occur as a normal phase variant and column with reversed phase. General trends in the development of methods for detecting chemical compounds using HPLC described in source (E. L. Stiskin, L. N. Itzykson, E. C. Braude. Practical high-performance liquid chromatography. -M.: Chemistry, 1986).As the closest analogue is selected Pat. The USSR, N 1349697, from which it follows that it is known the use of HPLC (according to U.S. Pat. USSR N 1349697 - liquid chromatography high resolution) to determine the two isomers of cypermethrin, belonging to the second enantiomeric pair /IR/S + /IS/R. the Definition of exercise on the stationary phase using an organic solvent, however, the conditions of the analysis and the possibility of defining other isomers of cypermethrin is not disclosed.The objective of the proposed isobilateral-1-carboxylic acid, in particular the 4 diastereomers in cypermethrine by HPLC.The proposed method for the determination of isomers of 3-phenoxy--Lebenshilfe ester 3-(2,2-dichloroethyl)-2,2-dimethylcyclopropane-1-carboxylic acid in cypermethrine is to chromatographic separation by HPLC of the sample on the stationary phase, representing the sorbent is silica-based, organic eluent from a mixture of hexane with tetrahydrofuran or ethyl acetate at a volume ratio of 100 : 0.1 to 0.6. Registration of the divided areas (peaks) is carried out using spectrophotometric detector at a wavelength of 254 nm. Mass fraction is calculated by the method of external standard peak areas. The sequence of output of 4 diastereomers cypermethrin:
1) /IR/R + /IS/S;
2) /IR/S + /IS/R;
3) /IR/R + /IS/S;
4) /IR/S + /IS/R.The chromatogram 16 - 22 minutes. The total error in determining the amount of the isomers is not more than 1.5%.Example 1.Pre-prepare two calibration solution cypermethrin - sample for calibration with a known percentage of each of the four diastereomers. For this purpose a portion of 25-40 mg of sample siperm is as eluent a mixture solvent of hexane and tetrahydrofuran in a volume ratio of 100 : 0,1. Similarly prepare two solutions of the samples analyzed cypermethrin (solutions N 3 and N 4). Using the dispenser injected aliquot (20 ál) of the resulting solutions into the flow of eluent in the following order: N 1, N 3, N 2, N 4, repeating enter two more times. The separation is carried out on a column (250 x 4.6 mm) with a fixed phase, representing a silica gel brand Ultrastar CN at a flow rate of eluent 1.1 ml/min Detection components carry out spectrophotometric detector at a wavelength of 254 nm. The mass percentage of each isomer is calculated by the method of external standard peak areas.The sequence of output of 4 diastereomers cypermethrin:
1) /IR/R + /IS/S;
2) /IR/S + /IS/R;
3) /IR/R + /IS/S;
4) /IR/S + /IS/R.On the obtained chromatograms calculate calibration factors (Kifor each isomer by the formula
< / BR>where marticle- the weight of cypermethrin sample for calibration;
Sithe peak area of i-isomer of cypermethrin in the chromatogram of the calibration solution;
Pi- mass fraction of i-isomer in cypermethrine - sample for calibration, %.Then calculate the mass percentage Xithe % of each of EPA cypermethrin;
mCR- the weight of the portion of the analyzed sample;
Sxithe peak area of i-isomer in the chromatogram of the analyzed sample.After calculating chromatograms receive the following contents of 4 diastereoisomers in the analyzed sample cypermethrin:
1) /IR/R + /IS/S - 0,6%;
2) /IR/S + /IS/R - 39,7%;
3) /IR/R + /IS/S - 0,6%;
4) /IR/S + /IS/R - 57.6 Per Cent.Example 2.The analysis is performed analogously to example 1 except for the volume ratio of the components of the eluent, which is hexane : tetrahydrofuran 100 : 0,2.After calculating chromatograms receive the following contents of 4 diastereoisomers in the analyzed sample cypermethrin:
1) /IR/R + /IS/S - 0,6%;
2) /IR/S + /IS/R - 39,0%;
3) /IR/R + /IS/S - 0,7%;
4) /IR/S + /IS/R - 57,0%.Example 3.The analysis is performed analogously to example 1 except for the volume ratio of the eluent components and brands of used sorbent. The ratio of the components eluent hexane : tetrahydrofuran of 100 : 0.3 to. As stationary phase using silica gel brand Ultrasphere Si.After calculating chromatograms receive the following contents 4 diastereomer the+ /IS/S - 0,6%;
4) /IR/S + /IS/R - 58,0%.Example 4.The analysis is performed analogously to example 1 with the exception of co-solvent in eluent, volume ratio of the components of the eluent, a flow rate of eluent and brands of used sorbent.As a co-solvent in eluent using ethyl acetate at a volume ratio of the components of the eluent hexane : ethyl acetate 100 : 0,4. As stationary phase using silica gel brand Ultrasphere Si. The rate of flow of eluent 2 ml/minAfter calculating chromatograms receive the following contents of 4 diastereoisomers in the analyzed sample cypermethrin:
1) /IR/R + /IS/S - 0,7%;
2) /IR/S + /IS/R - 39,2%;
3) /IR/R + /IS/S - 0,5%;
4) /IR/S + /IS/R - 58,6%.Example 5.The analysis carried out analogously to example 4 except for the volume ratio of the components of the eluent, which is hexane : ethyl acetate 100 : 0,6.After calculating chromatograms receive the following contents of 4 diastereoisomers in the analyzed sample cypermethrin:
1) /IR/R + /IS/S - 0,7%;
2) /IR/S + /IS/R - 40,1%;
3) /IR/R + /IS/S - 0,5%;
4) /IR/S + /IS/R - 56,6%. The method of determination of isomers of 3-f the objective liquid chromatography on a stationary phase using an organic solvent, characterized in that as the stationary phase used sorbent is silica-based and as eluent a mixture of hexane with tetrahydrofuran or ethyl acetate at a volume ratio of 100 : (0.1 to 0.6).
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