磁性石墨烯复合材料在蔬菜保鲜剂检测中的应用研究

发布时间：2019-04-20 16:27

【摘要】：保鲜剂通常用于蔬菜的保鲜,以防止其腐烂变质。而大多数的化学保鲜剂为农药,在使用过程中出现乱用、滥用、残留量超标等现象,已经严重威胁到消费者的身体健康。在食品安全越来越受到关注的情况下,寻求一种安全有效的除杂吸附剂用于样品前处理技术显得尤为重要。磁性纳米材料(Fe_3O_4)具有超顺磁性,在外加磁场的作用下可快速从溶液中分离。在分析检测中,利用其比表面积大和毒性低的优点,再将其与其他材料结合,可望提高提取效率和分离速度。石墨烯(G)是由碳原子以sp2杂化形成的只有一层原子厚度的二维晶体,具有超大的比表面积,大的共轭体系,能够耐酸、耐碱、耐热。在G的表面可进行功能化修饰以产生不同的作用效果。离子液体(IL)是由有机阳离子和无机或有机阴离子组成,在室温附近呈液态的有机盐类。IL因其具有热稳定性好、溶解能力强等优良性能被广泛应用于有机合成、催化、分离分析等领域。本文通过制备新型磁性石墨烯复合物作为净化吸附材料实现蔬菜中多种保鲜剂快速有效的检测。第一部分基于磁性石墨烯复合材料快速检测蔬菜中16种保鲜剂目的:基于Qu ECh ERS方法的原理,制备Fe_3O_4@Si O2@G新型复合材料,将其作为磁性固相萃取(MSPE)的吸附剂快速净化蔬菜样品,通过气相色谱质谱仪(GC-MS)同时检测蔬菜样品中16种保鲜剂。方法:采用化学键合法制备Fe_3O_4@Si O2@G,优化合成比例,以蔬菜为原料经乙腈提取,Fe_3O_4@Si O2@G除杂净化,用GC-MS外标法定量。结果:16种保鲜剂在0.02~2.00 mg/L范围内线性关系良好,相关系数(R2)为0.9946~0.9998,检测限(LOD)在0.21~11.50μg/kg之间,回收率为78.3%~116.7%,相对标准偏差为1.4%~11.9%。结论:本文制备的Fe_3O_4@Si O2@G具有良好的吸附能力和超顺磁性,极大地提升了分离速度,检测结果表明本方法具有快速、准确、灵敏度高等特点,能够应用于实际蔬菜样品中16种保鲜剂的测定。第二部分基于磁性石墨烯聚离子液体复合材料快速检测蔬菜中20种保鲜剂目的:制备200~1000 nm的磁性纳米粒(Fe_3O_4),合成Fe_3O_4@Si O2@G@PIL复合材料作为改进Qu ECh ERS法的吸附剂,结合气相色谱质谱(GC-MS)分析,建立快速测定蔬菜中20种保鲜剂的方法。方法:通过化学沉淀法控制合成条件,制备了不同粒径大小的Fe_3O_4,再分别制备不同粒径大小的Fe_3O_4@Si O2@G@PIL复合材料。以蔬菜为原料,经正己烷饱和的乙腈提取,将不同粒径的复合材料作为除杂吸附剂,并比较作用效果,用GC-MS外标法定量。结果:20种保鲜剂在0.02~2.00 mg/L呈现良好的线性,相关系数(R2)为0.9972~0.9999,检测限为0.82~6.64μg/kg。结论:制备的Fe_3O_4@Si O2@G@PIL复合材料具有良好的吸附性能,可应用于蔬菜样品中20种保鲜剂的高效快速检测。
[Abstract]:Preservatives are usually used to keep vegetables fresh to prevent their decay. The majority of chemical preservatives are pesticides, which appear in the process of use, abuse, residue exceeding the standard and other phenomena, has seriously threatened the health of consumers. In the case of more and more attention to food safety, it is very important to find a safe and effective adsorbent for sample pretreatment. Magnetic nanomaterials (Fe_3O_4) are superparamagnetic and can be rapidly separated from the solution under the action of external magnetic field. By using the advantages of large specific surface area and low toxicity, and combining it with other materials, the extraction efficiency and separation speed can be improved. Graphene (G) is a two-dimensional crystal with only one layer of atom thickness formed by the hybridization of carbon atoms with sp2. It has a large specific surface area and a large conjugate system, which can withstand acid, alkali and heat resistance. Functionalized modification can be performed on the surface of G to produce different effects. Ionic liquid (IL) is composed of organic cations and inorganic or organic anions. Il is a liquid organic salt near room temperature. Il is widely used in organic synthesis and catalysis because of its excellent properties such as good thermal stability, strong solubility and so on. Separation analysis and other fields. In this paper, the preparation of new magnetic graphene complexes as purification adsorption materials to achieve rapid and effective detection of a variety of preservative in vegetables. The first part is based on the magnetic graphene composite rapid detection of 16 kinds of preservative in vegetables objective: based on the principle of Qu ECh ERS method, Fe_3O_4@Si O _ 2 / G composite material was prepared. It was used as an adsorbent for magnetic solid phase extraction of (MSPE) to purify vegetable samples rapidly. Sixteen preservative agents in vegetable samples were simultaneously determined by gas chromatography mass spectrometry (GC-MS). Methods: Fe_3O_4@Si O 2 / G was prepared by chemical bonding method. The ratio of synthesis was optimized. Vegetables were extracted with acetonitrile and cleaned up by Fe_3O_4@Si O 2? G, and quantified by external standard method of GC-MS. Results: the linear range of 16 preservatives was 0.02 ~ 2.00 mg/L, the correlation coefficient (R ~ 2) was 0.9946 渭 g / kg, the detection limit was 0.21 ~ 11.50 渭 g / kg, the recovery was 78.3% ~ 116.7%, the correlation coefficient was 0.9946 ~ 0.9998, the detection limit was 0.21 ~ 11.50 渭 g / kg, and the recovery was 78.3%. The relative standard deviation is 1.4% and 11.9%. Conclusion: the Fe_3O_4@Si O 2 G prepared in this paper has good adsorption ability and superparamagnetism, which greatly improves the separation speed. The detection results show that the method is rapid, accurate and sensitive. It can be applied to the determination of 16 kinds of preservative in actual vegetable samples. The second part is based on the rapid detection of 20 kinds of preservatives in vegetables based on magnetic graphene polyionic liquid composites. Objective: to prepare magnetic nanoparticles (Fe_3O_4) of 200 渭 1 000 nm. A rapid method for the determination of 20 preservative agents in vegetables was established by synthesizing Fe_3O_4@Si O2@G@PIL composites as adsorbents for improved Qu ECh ERS method combined with gas chromatography mass spectrometry (GC-MS). Methods: Fe_3O_4, composites with different particle sizes were prepared by chemical precipitation method, and then Fe_3O_4@Si O2@G@PIL composites with different particle sizes were prepared respectively. Using vegetables as raw materials and acetonitrile saturated with n-hexane, composite materials with different particle sizes were used as adsorbents for impurity removal. The effects were compared and quantified by GC-MS external standard method. Results: the calibration curves of 20 preservatives were linear at 0.02 ~ 2.00 mg/L, the correlation coefficient (R2) was 0.9972 渭 g / kg. and the detection limit was 0.82 ~ 6.64 渭 g / kg.. Conclusion: the prepared Fe_3O_4@Si O2@G@PIL composites have good adsorption properties and can be used for the rapid and efficient detection of 20 kinds of preservative in vegetable samples.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;TS255.7

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