Surfactant Modified Magnetic Nano Materials And Their Application In The Analysis Of Environmental Organic Pollutants

Magnetic solid phase extraction?MSPE?as a new treatment method has been widely used in the environment monitoring.The magnetic adsorbents are as the most important part in the MSPE.The commercial price of magnetic meterials is too expensive.We make magnetic materials in our laboratory which can be used as magenetic adsorbent.It can be not only easy to control the reaction conditions,but also greatly cheap.In this paper,we use our self-made magenetic materals as magenetic adsorbent to detect four PUHs?linuron,chromatoluron,monuron,diuron?which in the water sample and soil sample.Three aspects were studied as follows:?1?The magnetic adsorbents are made and they will be modified of surfactants.It is a classical coprecipitation method.In alkaline conditions through optimizing drops plus time to ammonia synthesis of magnetic nanoparticles?Fe₃O₄MNPs?which will be made perfect adsorbents.Firstly,in order to reduce the phenomenon of reunion,the magnetic adsorbents will be modified of SiO₂.Secondly,the Fe₃O₄MNPs/SiO₂ will be modified with sodium dodecul sulfate?SDS?.To make the Fe₃O₄ MNPs surface adsorption compound cavity and make sure the particle size smaller and better dispertion,we will optimizing the volunme of SiO₂ and the amound of SDS.The magnteic adsorbents were characterized by scanning election microscope and Fourier transform infrared Spectroscopy.?2?A nanocomposite comprised of Fe₃O₄ magnetic meterials were used as absorbent in the determination of 4 PUHs in water samples by MSPE and quantification by ultra-high performance liquid chromatography tandem mass spectrometry?UHPLC-MS/MS?.The magnetic adsorbents which made in the lab are compared with commercialization magnetic materials Several factors was optimized the best conditions were as follows,such as the type of active solvent,the amount of absorbent,pH,the type and amount of elution solvent,desorption time and so on.The optimized conditions were as follows: the recoveries of 4 PUHs in the water samples were ranged from 86.2% to 95.4%,under 5.0 of pH value,using 70 mg of synthesis nanomaterials,5m L of acetonitrile and 80 KHz ultrasonic frequency as activation solvent and 15 min of vibration time.The linearity were ranged from0.05 to 5.0?g/L with correlation coefficients more than 0.999.The method detection limits were between 10.9 and 13 ng/L with RSD in the range of 3.0%-6.6%.This method was sample and sensitive.It can decrease organic pollution to the environment during the determination of the pheulurea herbicides.?3?A method was developed for the determination of 4 PUHs in soil,based on ultrasonic extraction,?MSPE?and the subsequent analysis by UHPLC-MS/MS.Firstly,the extraction liquid are drid with nitrogen.Secondly,we add water to transport the targets to purificate with MSPE.The influences of several parameters,such as the type of solvent,frequency of ultrasound,extraction time,initial ultrasonic temperature,different dilute water volume,the amount of magnetic materials,desorption time and the amount of elution solventon the recoveries of anlytes were investigated.Under the optimized conditions:frequency of ultrasound 80 KHz,10m L alcohol,40?initial ultrasonic,15 min ultrasonic time,150 m L dilute water,100 mg amount of magentic absorbent,25 min desorption,6m L acetonitrile,the recoveries of 4 PUHs in soil were from 79.8-85.2%.The linearity were ranged from 5 to 200?g/kg with correlation confficients more than 0.995.The method detection limits were between 0.2 and 0.7 ?g/kg with RSD in the range of 4.6 to 7.9%.The proposed method is suitable for the determination of 4 PUHs in soil with high accuracy and precision.