CHINA RECOGNIZED INTRENATIONAL MUTUAL RECOGNITION TEST TESTING CNAS L13989
CHINA RECOGNIZED INTRENATIONAL MUTUAL RECOGNITION TEST TESTING CNAS L13989
Polycyclic aromatic hydrocarbons (PAHs), also known as: polyaromates, polyaromatic hydrocarbons, are two or more benzene rings arranged together in linear, angular and cluster shape, which are a kind of highly inert and stable polycyclic compounds, mainly from organic compounds. Among them, the natural sources include: volcanic eruption, forest vegetation and Bush burning, and the biochemical effects of bacteria on animals and plants. However, human activities, especially the combustion of fossil fuels, are the main sources of PAHs. PAHs in the atmosphere exist in the form of gas and adsorbed on the floating dust, which can directly enter the surface through dry and wet deposition, and can also make long-distance migration through air flow and wind, and then fall to the surface; PAHs can enter the soil through various ways such as wastewater irrigation, atmospheric dust fall, etc. The development of industry and the extensive use of fossil fuels have caused PAHs pollution in some areas of the world.
Polycyclic aromatic hydrocarbons (PAHs) are the first and most abundant carcinogens with carcinogenicity, teratogenicity and mutagenicity. At present, more than 400 kinds of carcinogenic PAHs and their derivatives have been found, and about several hundred thousand tons of PAHs are discharged into the atmosphere every year. Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic pollutants widely existing in the environment, and are also the first chemical carcinogens discovered and studied. Because of its toxicity, bioaccumulation, semi volatility and persistence in the environment, it has been listed as a typical persistent organic pollutant (POPs) and has been widely concerned by the international scientific community.
Polycyclic aromatic hydrocarbons with carcinogenic effect are mostly four to six ring fused ring compounds. Most PAHs are insoluble in water, with melting point of 101 ℃ ~ 438 ℃, boiling point of 150 ℃ ~ 525 ℃ and molecular weight of 178 ~ 300. PAHs of bicyclic and tricyclic are easy to degrade, while PAHs of tetracyclic and above are extremely difficult to degrade. The results show that: in indoor environment, the half-life of bicyclic PAHs is 2 days; the half-life of tricyclic PAHs is 16 days (anthracene), 134 days (phenanthrene); and the half-life of tetracycline PAHs is more than 200 days.
Classic GC / FID, GC / MS and HPLC are widely used in the separation and analysis of PAHs. Due to the advantages of high performance liquid chromatography in the separation of complex PAHs, EPA has published some effective methods for the analysis of drinking water (550.1 method), industrial and municipal wastewater (610 method), solid waste (9310 method) and atmosphere (3b-13 method) Polycyclic aromatic hydrocarbons. High performance liquid chromatography (HPLC) has many advantages, such as no need of high temperature, high resolution and sensitivity for some PAHs, and easy to collect the fraction after column for spectral identification. PAHs were determined by HPLC with UV, fluorescence and diode array detector.
In this project, 18 PAHs were separated and analyzed rapidly in 15 minutes by using varian920-lc high performance liquid chromatography and varianpursuit tmpah column and 8310 method issued by EPA. At the same time, 18 PAHs standards were injected 48 times. The results showed that the RSD of retention time was less than 0.4%. In this way, the consumption of reagents and time is greatly saved, and the analytical flux is improved. Compared with the conventional method, more PAHs compounds can be separated and analyzed at one time.
