基于磁性纳米材料Fe_3O_4/C吸附测定水样中痕量结晶紫的方法

Preparation of Fe_3O_4/C Magnetic Nanomaterial and Its Application in Detection of Trace Crystal Violet in Water

采用溶剂热/水热法合成了磁性纳米粒子Fe3O4/C,利用透射电镜、傅里叶变换红外光谱、X射线衍射等对其进行表征。将该材料用作磁性固相萃取吸附剂萃取富集水中的痕量结晶紫,之后用紫外分光光度法测定,建立了一种分离富集和检测结晶紫的方法。考察水样酸度、搅拌时间和吸附温度对结晶紫吸附率的影响。结果显示,在p H 8.0、搅拌时间10 min、吸附温度25℃条件下,该材料对结晶紫具有良好的吸附性,用乙醇-0.5 mol/L对甲苯磺酸（9∶1,V/V）可以很好地解吸。在优化实验条件下,方法对结晶紫的检出限为0.024 mg/L。对赣江水样品中的结晶紫进行检测,加标回收率为105.8%-108.4%,相对标准偏差为3.6%-6.1%。

A magnetic nanoparticle Fe3O4/C was prepared by solvothermal/hydrothermal method and characterized by transmission electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction. Using the material as a magnetic solid phase extraction sorbent, a new method for the detection of trace crystal violet（CV） in water was established by UV spectrophotometry. Effects of several factors including sample p H stirring time, and adsorption temperature on the percent adsorption of CV were investigated. The optimum adsorption conditions were determined as follows： p H, 8.0; stirring time, 10 min; and temperature, 25 ℃, and high desorption efficiency was achieved using ethanol-0.5 mol/L p-toluenesulfonic acid（9：1, V/V） as the eluent. Under the optimum conditions, the limit of detection（LOD） of this method was 0.024 mg/L. The proposed method was applied to the determination of CV in Ganjiang river water with spiked recoveries of 105.8%–108.4% and relative standard deviation（RSD） of 3.6%–6.1%, respectively.