Application of Gas Chromatography in Environmental Science

Application of Gas Chromatography in Environmental Science

⑴ Analysis of trace carbon monoxide in the atmosphere
Car exhaust contains carbon monoxide, and incomplete combustion of industrial boilers and household coal stoves releases carbon monoxide, which pollutes the environment. Trace carbon monoxide in the atmosphere is usually determined by conversion method. The domestic SP-2307 chromatograph has a conversion device to convert CO into CH4. CO+3H2Ni catalysis/380℃→CH4+H2O The stationary phase of the chromatographic column can be 5A sieve molecules, GDX-104, Porpak Q, etc. Taking molecular sieve as an example, 13X or 5A molecular sieve 60~80 mesh (first activated at 500~550℃ for 2 hours) with hydrogen carrier gas, 57ml/nin; hydrogen flame detector; air 400ml/min; tail nitrogen 80ml/min. Column length 2m, inner diameter 2mm, column temperature 36℃, detection chamber 130℃, converter 380v; injection volume 1mm. It can measure ppm-level carbon monoxide in the atmosphere.

⑵ Analysis of benzene series in air
The commonly used method is to use a column with a length of 2m and an inner diameter of 3mm; filled with 10% PEG20M/101 white support 60~80 mesh; column temperature 120℃, vaporization chamber 150℃, detection chamber 150℃; carrier gas nitrogen flow rate 60ml/min; 57ml/nin; hydrogen flame detector; hydrogen 35ml/min, air 400ml/min. It is very good for separating benzene, toluene and xylene. It can also be coated with non-polar apisone or squalane. If the three isomers of xylene need to be completely separated, a mixed stationary liquid of organic bentonite and dinonyl phthalate can be applied to the 6201 support, or a mixed stationary liquid of organic bentonite and diglycerol can be used, and the three bodies can be well separated. 6201 is the adsorbent, adsorption temperature is -78℃, desorption is 100℃, concentration is 100 times, recovery rate is 100%, chromatographic column is 40% N,N-bis(9_cyanoethyl)formamide/6201, 80~100 mesh, column temperature is 100℃, hydrogen flame detector, minimum benzene is 5ppb.

⑶ Analysis of organic halides in water
Chloroform, carbon tetrachloride, 1,2-dichloroethane and other organic halides will be produced after chlorination of tap water. Chloroform has been used for monitoring abroad. Chloroform is a volatile liquid and can be analyzed by headspace gas chromatography. The gas phase that reaches equilibrium with the sample is taken for analysis. The chromatographic column used is 2m long, 3mm inner diameter, U-shaped column; filled with 25% PEG6000+0/5DC-200/Chromosorb W60~80 mesh, divided into 1:1 sections. Column temperature 102℃, vaporization and detection 250℃, electron capture detector; high-purity nitrogen as carrier gas 35ml/min. Air, carbon tetrachloride and chloroform are well separated.