表面活性剂修饰磁性纳米材料及其在环境有机污染物分析中的应用

发布时间：2018-01-17 23:27

本文关键词：表面活性剂修饰磁性纳米材料及其在环境有机污染物分析中的应用　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：磁性固相萃取作为一种新型的前处理方式在环境监测领域已经得到了广泛的应用,其核心组成部分是磁性吸附材料,但是商品化的磁性材料合成条件较为苛刻,且价格过于昂贵,实验成本较高。通过实验室自制的磁性材料作为磁性固相萃取的吸附剂,不仅合成步骤较为简单,也可大大降低实验成本。本文主要是通过实验室自制的磁性纳米材料,并用表面活性剂对其修饰,将修饰后的磁性材料用作磁性固相萃取中的吸附剂对水样和土壤样品中常见的四种苯脲类有机污染物(灭草隆、敌草隆、绿麦隆、异丙隆)进行测定,主要研究内容:(1)磁性吸附剂的合成:采用经典的共沉淀法,在碱性条件下通过优化滴加氨水的时间来合成磁性纳米粒子(Fe_3O_4MNPs)。将合成的Fe_3O_4MNPs先用SiO_2修饰,以减少Fe_3O_4MNPs的团聚现象,再用十二烷基硫酸钠(SDS)修饰,使Fe_3O_4MNPs表面具有吸附化合物的孔穴。通过优化SiO_2以及SDS的用量,使得所制备的磁性材料粒径更小,分散性更好。将合成的磁性材料进行扫描电镜和傅里叶红外表征。合成出的磁性材料表面具有很多的孔穴,对待测物质具有吸附性。(2)用实验室自制的磁性材料作为磁性固相萃取中的吸附剂,并结合超高效液相色谱-质谱法测定水样中的四种苯脲类化合物,并与商品化的磁性材料进行了对比。考察了活化溶剂种类及用量、磁性材料的种类及用量、pH、酸的种类、洗脱溶剂的种类及体积、振荡时间等因素对四种苯脲类除草剂回收率的影响。确定最佳优化条件为:50m L的水样用盐酸调节到pH=5,活化溶剂为5m L的乙腈,80KHz超声分散3min,磁性吸附剂的用量为70mg,洗脱溶剂为4m L乙腈,振荡15min,四种待测物质的加标回收率在86.2%-95.4%之间。方法的线性范围是0.05-5.0μg/L,相关性系数都大于0.999,相对标准偏差3.0-6.6%,方法检出限(LOD)范围为10.9-13.3ng/L。用乙腈浸泡磁性材料,然后低温烘干后重复利用。磁性材料经过多次的重复使用,未见待测物质的回收率有明显下降趋势。该方法具有快速、灵敏、磁性材料可重复使用且减少分析过程中有机试剂对环境污染等优点。(3)采用超声提取法先提取土壤中的四种苯脲类物质,将提取液氮吹近干后加入水稀释复溶,将磁性固相萃取法用作土壤中待测物的净化技术,建立了土壤中四种苯脲类除草剂的前处理方法,并采用超高效液相色谱质谱法进行定性定量分析。并将磁性固相萃取法与固相萃取法进行了对比。考察了萃取溶剂、超声频率、萃取时间、初始超声萃取温度、稀释水样体积、磁性纳米材料的用量、振荡时间、洗脱溶剂的体积对土壤中待测物质回收率的影响。最佳萃取条件是:10m L乙醇在80KHz条件下超声15min,初始超声温度为40℃。净化条件是:150m L的稀释水样,100mg的磁性吸附材料,25min振荡时间,6m L乙腈洗脱。回收率在79.8~85.2%之间,方法的线性范围是5-200μg/kg,相关性系数都大于0.995,相对标准偏差4.6-7.9%,方法检出限(LOD)范围为0.2-0.7μg/kg,该方法具有操作简便,检出限低,灵敏度高等特点,适用于土壤中痕量苯脲类物质的测定。
[Abstract]:Magnetic solid phase extraction as a new pretreatment method has been widely used in the field of environmental monitoring, the core part is the magnetic adsorption materials, magnetic materials but commercial synthesis conditions are harsh, and the price is too expensive, the high cost of experiment. Through the self-made magnetic material as magnetic adsorbents for solid-phase extraction not only, the synthesis step is relatively simple, but also can greatly reduce the experimental cost. This paper is mainly through the self-made magnetic nano materials, and surfactant on the modification, the magnetic material of modified magnetic solid phase extraction as adsorption agent on water and soil samples of four kinds of common phenylureas organic pollutants (monuron and diuron and Chlortoluron and isoproturon) were determined. The main research contents are as follows: (1) the synthesis of magnetic adsorbents by co precipitation method in the classic, alkaline conditions Under the optimized by adding ammonia time to synthesis of magnetic nanoparticles (Fe_3O_4MNPs). The first synthesis of Fe_3O_4MNPs modified with SiO_2, in order to reduce the agglomeration of Fe_3O_4MNPs, with twelve sodium dodecyl sulfate (SDS) modification of the Fe_3O_4MNPs surface hole with adsorption compounds. Through the optimization of SiO_2 and the amount of SDS, makes the magnetic the material with smaller size particle preparation, better dispersion. The magnetic material is synthesized by scanning electron microscopy and Fourier transform infrared spectra. The synthesized magnetic material surface has many holes, measured with adsorption material. (2) with self-made magnetic materials as adsorbent magnetic solid phase extraction, and determination of four phenylurea compounds in water using ultra high performance liquid chromatography-mass spectrometry, compared with commercial and magnetic materials. The effect of activation of solvent type and amount, the kind of magnetic material Type and dosage, pH, acid type, type and volume of elution solvent. The effect of oscillation time and other factors on four herbicides recovery. Determine the best optimized condition is: 50m L water sample with hydrochloric acid to adjust to pH=5, activation of acetonitrile solvent for L 5m, 80KHz 3min, ultrasonic dispersion, magnetic adsorption the dosage is 70mg, elution solvent is 4m L acetonitrile, 15min four kinds of oscillation, the recovery rate of the substance to be tested in 86.2%-95.4%. The linear range is 0.05-5.0 ~ g/L, the correlation coefficient is greater than 0.999, the relative standard deviation is 3.0-6.6%, the detection limit of the method (LOD) with acetonitrile immersion magnetic materials for 10.9-13.3ng/L. then, low temperature drying after repeated use of magnetic materials. After used repeatedly, no analyte recovery rate decreased significantly. The method is rapid, sensitive, magnetic materials can be reused and reduced in the process of organic analysis Reagents on environmental pollution and other advantages. (3) extract in soil four phenylurea compounds extracted by ultrasonic extraction method, adding water blown nearly dry after liquid nitrogen dilution solution, the magnetic solid phase extraction method for the purification technology of soil analytes, established a pretreatment method of four phenylureas the herbicide in the soil, and the use of mass spectrometry UPLC qualitative and quantitative analysis. Comparing the magnetic solid phase extraction and solid-phase extraction method. The effects of extraction solvent, extraction time, ultrasonic frequency, ultrasonic extraction and initial temperature, dilution water volume, magnetic nano material dosage, oscillation time, elution solvent the volume of soil to be measured in the material recovery rate. The best extraction conditions are: 10M L 80KHz 15min in ethanol ultrasonic conditions, initial temperature of 40 DEG. Ultrasonic purification conditions are: dilution water 150m L, magnetic adsorbent 100mg, 2 5min 6m L oscillation time, acetonitrile. The recovery rate was 79.8~85.2%, the linear range is 5-200 ~ g/kg, the correlation coefficient is greater than 0.995, the relative standard deviation is 4.6-7.9%, the detection limit of the method (LOD) is in the range of 0.2-0.7 g/kg, this method has the advantages of simple operation, low detection limit, high sensitivity, suitable for determination of soil trace phenylurea compounds.

【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X830;TB383.1

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