Universal gas chromatographGas is used as the flowing relative analytical substance for chromatographic analysis. Mainly used for the analysis of low molecular weight volatile organic compounds, in surface water environmental quality standards,80In the analysis of specific projects related to drinking water, there are57The method used is gas chromatography.

Gas chromatography has(1)High separation efficiency(2)HIGH SENSITIVITY(3)high selectivity(4)Fast analysis speed(5)Features with a wide range of applications

Universal gas chromatographIn the field of water quality monitoring and detection of chemical pollutants, it is mainly used for monitoring organic chlorine pesticides, organic phosphorus pesticides, organic chemical pollutants, and trace metal elements.

Application of Gas Chromatography in the Detection of Organochlorine Pesticides

Organochlorine pesticides are neurotoxic and also hepatotoxic. Organochlorine pesticides have a long residual period, are not easily decomposed, cause serious pollution to the environment, and have adverse consequences such as teratogenicity. Gas chromatograph equipped with electronic capture detector, using inner diameter2～3．5mm, Long1．8～2mA hard glass pillar, built-inChromosorb WAWDMCS 80—100Eyes, paintOVone17do1．5％，QFone1do1．95%Set column temperature180℃ Temperature of vaporization chamber200℃, detector temperature220℃ , nitrogen carrier gas(≥99．999％)The flow rate is60mL／minCan detect "666" in water bodies(contain4Species of isomers, detectable4ng／L)andDDT (contain4Species of isomers, detectable200ng／L)And organic chlorine pesticide ingredients such as Ai reagent, heptachlor, and endosulfan.

Universal gas chromatographApplication in the detection of organophosphorus pesticides

Organophosphorus pesticides are mostly phosphate esters or thiophosphate esters, and they are mostly oily liquids. Industrial products are light yellow to brown in color and have a garlic odor. Generally insoluble in water, but soluble in organic solvents and animal and vegetable oils. It is relatively stable to light, heat, and oxygen, and easily decomposes and destroys when exposed to alkali. Organophosphorus pesticides can enter the human body through the digestive tract, respiratory tract, and intact skin and mucous membranes. The organic phosphorus pesticides absorbed by the human body are distributed in various organs, with the liver having a higher content.

gas chromatographConfigure flame photometric detector with inner diameter4mm, Long2mA hard glass column with a white acid washed silanized diatomaceous earth support, coatedDCone200do5%TheQFone1do7．5%Set column temperature170℃, vaporization chamber temperature240℃ , detector temperature230Y3, carrier gas(Nitrogen, ≥99．99％)The flow rate is60mL／min， combustion gas(Hydrogen gas, ≥99．99％)The flow rate is160 mL／minCan detect organophosphorus pesticides such as methyl parathion, parathion, malathion, dimethoate, and dichlorvos, and the detection limit is usually within5×10—4～10～mg／L.

gas chromatographApplication in the detection of organic chemical pollutants

The gas chromatograph is equipped with a hydrogen flame ionization detector, and with appropriate detection conditions, it can detect trichloromethane in water(Low detection limit0．000 6mg／L)Carbon tetrachloride(Low detection limit0．000 3mg／L)Trichloroethylene(Low detection limit0．OO3mg／L)Tetrachloroethylene(Low detection limit0．001 2mg／L)Toluene(Low detection limit0．01mg／L)Nitrobenzene(Low detection limit0．000 2mg／L)Aniline(Low detection limit0．002mg／L)Acrylamide(Low detection limit0．000 15mg／L)Methylmercury(Low detection limit1 X 10mg／L)class50Organic pollutants in various water bodies.

Universal gas chromatographApplication in the detection of trace metal elements

Gas chromatography is an important method for analyzing and detecting organic pollutants, and in recent years, it has also made progress in analyzing certain trace metal elements in water. The metal elements that can be analyzed by gas chromatography now include selenium, beryllium, copper, etc. The method for analyzing and detecting selenium is to utilize1，2When a phenylenediamine or derivative reacts with tetravalent selenium in an acidic solutionO～PDAWhen the reagent is sufficient, it can quantitatively generate volatile compounds that can be organically extracted as phenylpropanoid selenidazole compounds, and then measure their content using a gas chromatograph with an electron capture detector.

By utilizing the characteristics of gas chromatography, water environment monitoring workers can quickly and accurately analyze residues of benzene, toluene, xylene, styrene butadiene naphthalene, organic chlorine, organic bromine and sulfur, phosphorus pesticides, etc. in water bodies50Pollution caused by various organic toxins.