METHOD OF IDENTIFYING DIETHYLAMINE AND ISOPROPYL ALCOHOL IN GAS MIXTURES Russian patent published in 2016 - IPC G01N30/00 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry of organic compounds and can be used for identification of diethylamine and isopropyl alcohol in gas mixtures. Method of identifying diethylamine and isopropyl alcohol in gas mixtures is characterized with that as the test devices for identification of diethylamine and isopropyl alcohol an array is used of four piezo-quartz resonators with the natural oscillation frequency of 10 MHz, electrodes of which are modified by applying on them individual solutions of bee wax (BW), polyethylene glycol sebacate (PEGS), polyethylene glycol phthalate (PEGF) and apiezon L (ApL) in such a way, that the weight of each film of the sorbent after the solvent removal by drying in a drying chamber at the temperature of 40-50 °C during 15-20 min is of 15-20 mcg, which then are put into a closed detection cell of "MAG-8" multichannel gases analyzer and kept therein for 5 minutes to establish a stable zero signal. Then 5.0 g of the analyzed finely ground sample are placed into a glass sampler of 50 cm³ volume, for example, a blocked plastic article or an item with thin-film coating with the surface area of 100 cm², the sampler is tightly closed with a polyurethane plug, maintained at the temperature of 20±1 °C during 15 minutes to obtain an equilibrium gas phase. Then the content of diethylamine and isopropyl alcohol is determined as per signals of sensors, for which in case of the blocked plastic article or the item with thin-film coating 5 cm³ of the equilibrium gas phase are taken from the sampler using a syringe through a polyurethane plug or the same volume in case of another gas mixture and it is injected into the closed detection cell of “MAG-8” multichannel gases analyzer with the help of software, which contains a program for reading maximum signals from all the sensors, changes of each piezo-sensor oscillation frequency of ΔF, Hz are read for 60 sec and the ratio of sensors responses - parameters $$A_1=\frac{\Delta F(BW)}{\Delta F(PEGS)}$$ and $$A_2=\frac{\Delta F(PEGF)}{\Delta F(ApL)}$$ is calculated. Conclusion is made on presence of diethylamine in the mixture in case parameter A₁ is equal to 0.13±0.03, and if the gas mixture contains isopropyl alcohol parameter A₂ is of 2.0±0.4.

EFFECT: technical result is development of method of identifying diethylamine and isopropyl alcohol in various gas mixtures making it possible to identify them without a multistage sample preparation, to provide high sensitivity, accuracy and rapidness.

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