The method of determination of toxic substances in gas mixtures

 

(57) Abstract:

Use: for detection of toxic substances in gas mixtures. The inventive gas mixture is passed through a polymeric adsorbent, which is the carboxyl-containing porous material, characterized by porosity 90-99,9%, and the content of carboxyl groups 1-13 mmol/g of polymer, followed by desorption by heating. The received gas flow is passed through the detector, where they perform surface ionization and analysis by plasma chromatography. The heated during desorption carried out by a sharp rise in temperature or by flash. Toxic substances definition, are narcotic, explosive substances, i.e. substances containing nitrogen-containing groups and compounds containing alkyl compounds of phosphorus or arsenic. 1 C. p. F.-ly, 2 C.p. f-crystals, 1 table.

The invention relates to a developing method of analysis of various toxic substances, and the proposed method can detect them in the trace.

There is a method of analysis of organic impurities in the air by use of the device containing the adsorber, which use polymer (polite the La extraction of impurities with subsequent chromatographic analysis. The method compares favorably with other well-known absence of liquid media [1]

The disadvantage is the limited application of the method, because it is applicable to the analysis of only hydrocarbons of aromatic character, containing no heteroatoms.

Closest to the claimed method is a method of analysis of toxic substances in the air [2] which is as follows: the gas stream containing toxic substances, in particular light amines, is subjected to concentration by passing the mixture through a polymeric sorbent. The polymeric sorbent is a compound based on polytetrafluoroethylene. Then carry out the desorption concentrate heat stroke and analyze the resulting mixture in a stream of inert gas by passing it through physico-chemical detector. In the operation of the detector used-ionization flow with subsequent analysis of the ions.

The disadvantage of this method is that the number of stages (stage ionization and subsequent) requires the use of an inert gas. Use as a polymeric sorbent (membrane in the form of a film) fluorine-containing polymer degrades the quality of the analysis, increasing the lower threshold qualitative determination of the analyzed what this also reduces the possibility of determining low concentrations of toxic volatile amines, which varies in the interval 5-1510-9g/l

An object of the invention is to provide a method allowing to determine very low concentrations similar to the closest analogue of toxic substances (volatile amines) in the analyzed stream, to determine their qualitative presence, starting with a concentration of 10-11g/l (or 10-13mol/l) and above.

The method allows qualitatively and quantitatively to determine the toxic organic compounds containing other elements of the V group main-group elements of the periodic table, which are not determined in a known manner.

The need of this type of analysis is constrained in some cases by the need in a short time to determine the presence of, for example, are prohibited for carriage of cargo inspection services, the occurrence of leakage from the tanks when the quality control of goods, in particular food purposes, when such substances are formed as the reaction product. The method is universal in respect of amine, amide and other nitrogen groups in any of the compounds containing them, preferably in the absence of interfering with the analysis of atoms, i.e. compounds can contain atoms of carbon, hydrogen, oxygen, metals, and prob is a date. In a series of toxic substances to be determined, in particular, are drugs and explosives. As gas mixtures can be analyzed air mixture in the premises of railway stations, manufacturing plants, etc.

This object is achieved in that the working stream containing an analyte is passed through the layer of polymeric sorbent. The polymer used as the adsorbent, is a carboxyl-containing content of COOH-groups 1-13 mmol/g of dry polymer, and is characterized by porosity 90-99,9% and then for desorption using heat. It may be heat stroke, flash, quick short-time heating and other Temperature must be sufficient for desorption, it is even possible decomposition of the sorbent. After desorption stream is passed through physico-chemical detector, where the use of surface ionization with subsequent gas electrophoresis (plasma chromatography).

Examples 1-7 of the method.

Workflows, including air and contained impurities:

toxic compounds containing NH2group (thread 1);

toxic substances, containing hydrazine powered group (stream 2);

the Ana (stream 4);

substances containing amides (stream 5);

a stream containing alkyl derivatives of phosphorus and arsenic (threads 6 and 7, respectively),

passed through the layer of polymeric sorbent containing 1-13 mmol carboxylic groups per gram of adsorbent. As the polymer can be used, modified carboxymethylcellulose, polyvinyl alcohol, dextranase polymers and others After adsorption necessary desorption of the analyte. This is implemented by a short sharp rise in temperature. The resulting stream containing an analyte, and a background thread is subjected to surface ionization with subsequent chromatography. the presence of inert gas is not necessary.

The results of the analysis are presented in the table.

Thus, the proposed method against toxic substances (drugs and explosives containing volatile amines) to expand the boundaries of high-quality detection, to detect them in smaller quantities, present in the air. Furthermore, the method allows to analyze and other toxic organic compounds containing heteroatoms from the group V elements of the periodic table, i.e., to expand the scope. With the practical substances in gas mixtures by passing the gas mixture through a porous polymeric material with subsequent desorption of the adsorbed substances, ionization of the received gas flow and its analysis, characterized in that the porous material used carboxyl-containing polymeric material with a porosity of 90.0 to 99.9% and the content of carboxyl groups 1 13 mmol/g of polymer, after desorption of the resulting mixture is subjected to surface ionization with subsequent analysis of the mixture of plasma chromatography, the toxic substances identify organic compounds that contain atoms of the fifth main group elements of the periodic table.

2. The method according to p. 1, characterized in that the desorption carry out a short sharp increase in temperature or by the use of fire outbreaks.

3. The method according to p. 1, characterized in that toxic substances definition, are alkyl phosphorus or arsenic, compounds containing amine, amide, hydrazine powered, gidrazonami, tetrazona group.

 

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