In China's environmental scientific research, supervision and testing, gas chromatography is widely used to determine trace amounts of harmful substances in the atmosphere and water.
â‘´Analysis of trace carbon dioxide in the atmosphere
Car exhaust contains carbon monoxide, and industrial boilers and household coal stoves do not completely emit carbon monoxide, which pollutes the environment. Common conversion methods for trace amounts of carbon monoxide in the atmosphere are uncertain. The domestic SP-2307 chromatograph has a conversion device to convert CO to CH4. CO + 3H2Ni catalyst / 380 ℃ → CH4 + H2O column stationary phase can use 5A sieve molecule, GDX-104, Porpak Q, etc. Taking molecular sieve as an example, 13X or 5A molecular sieve 60 ~ 80 mesh (first activated by 500 ~ 550 ℃ Hour) with hydrogen carrier gas, 57ml / nin; hydrogen flame detector; air 400ml / min; tail gas nitrogen 80ml / min. The column length is 2m, the inner diameter is 2mm, the column temperature is 36 ℃, the detection chamber is 130 ℃, the conversion furnace is 380v; the sample injection volume is 1mm. It can measure ppm carbon monoxide in the atmosphere.
⑵Analysis of benzene series in the air
The common method is to use a column with a length of 2m and an internal diameter of 3mm; filled with 10% PEG20M / 101 white support body 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. The separation of p-benzene, toluene and xylene is very good. Non-polar columns such as aspirin or squalane can also be used. If the three isomers of p-xylene are to be completely separated, the mixed fixative solution of organic bentonite and dinonyl phthalate can be applied to the 6201 support, or the mixed fixative solution of organic bentonite and diglycerin can be used. Get a good separation. 6201 is an adsorbent, the adsorption temperature is -78 ℃, the desorption temperature is 100 ℃, the concentration is 100 times, the recovery rate is 100%, the chromatographic column is 40% N, N-bis 9_cyanoethyl) formamide / 6201, 80 ~ 100 mesh, A hydrogen flame detector with a column temperature of 100 ° C and a benzene minimum of 5ppb.
⑶Analysis of organic halides in water
After chlorination of tap water, organic halides such as chloroform, carbon tetrachloride, and 1,2-dichloroethane are produced. Chloroform has been used for monitoring abroad. Chloroform is a volatile liquid, which can be analyzed by headspace gas chromatography, and the gas phase in equilibrium with the sample is used for analysis. The chromatographic column used is 2m long, 3mm internal diameter, U-shaped column; filled with 25% PEG6000 + 0 / 5DC-200 / Chromosorb W60 ~ 80 mesh, packed in 1: 1 segments. Column temperature is 102 ℃, vaporization and detection is 250 ℃, electron capture detector; high purity nitrogen is carrier gas 35ml / min. Air, carbon tetrachloride and chloroform are well separated.
• Elegant and professional finish
• Full access to all controls and ports
• Provides perfect protection against dust, bump or scratch
we employ the most creative designers and tech brilliant engineers to make the best cases. We believe our high-quality products with competitive prices will satisfy your needs.
The productive process :
Make the Products Mould –Cutting the fabric –Do the half products – Finish products – Cleaning –QC- Package – Shippment .
Key Chain
Mobile Cover,Phone Sleeve,Cell Phone Sleeve,Phone Cover Case
Guangzhou Ysure Electronic Technology Co., Ltd. , https://www.ysurecase.com