磁性Fe_3O_4@SiO_2-SH的制备及环境水体中汞的富集与分析

Prepare of Fe_3O_4@SiO_2-SH and its application for preconcenration of mercury from enviromental water

制备了一种新型的磁性纳米吸附剂—巯基修饰的Fe3O4@SiO2,并将其用作固相萃取剂从环境水样中富集痕量Hg^2＋,采用原子荧光分光光度计测定富集后的Hg^2＋。研究了吸附剂用量、pH、平衡时间、洗脱条件及吸附剂重复使用次数对Hg^2＋回收率的影响。利用该磁性固相萃取方法建立了标准曲线,并用于测定实际水样中的Hg^2＋含量。方法的检测限为0.1 ng/L,加标回收率为95%-104%,相对标准偏差0.1%-0.6%。

Mercury exists in environmental water at trace level. To monitor trace mercury pollution in environment water,preconcentration and purification are necessary before instrument measurement. There are some disadvantages in traditional methods,such as low efficiency,fussy operation,time-consuming. In this study a novel Fe3O4@ Si O2-SH sorbent was synthesized and used as a solid phase extraction（ SPE） sorbent to extract trace Hg2 ＋from environmental water samples,and then the concentration of Hg2 ＋was determined with a hydride generation-atomic fluorescence spectrophotometer. Effects of amount of sorbent, solution p H,equilibrium time,desorption condition,and recycle time on recovery of Hg2 ＋were studied in detail. The standard curve was obtained based on the magnetic SPE method,and the proposed method was successfully applied to the determination of trace Hg2 ＋in some environmental water. The detection limit was 0. 1 ng / L,and the recoveries rates of the spiked water samples ranged from 95% to 104% with relative standard deviations（ RSD） varying from 0. 1% to 0. 6%,exhibiting high sensitivity,wide linear range and good precision. This study not only developed a simple, convenient, and high sensitive method to determine trace Hg2 ＋in environmental water,but also opened up a new avenue for application of magnetic SPE.