分子印迹功能介孔材料富集-火焰原子吸收光谱法测定溶液中痕量铅

以2-巯基苯骈噻唑为修饰剂,铅离子为印迹离子成功制备分子印迹功能介孔材料,并用扫描电镜(SEM)、傅里叶红外光谱对材料进行了结构表征。铅离子分子印迹功能介孔材料能很好地将Pb(II)与性质相近的二价重金属离子Cu(II),Cd(II)和Hg(II)分离,具有非常好的吸附选择性,且静态吸附容量0.64 mmol/g。利用该材料制备的分离富集柱可以很好地富集溶液中痕量铅离子,且仅用2 mL 0.5 mol/L EDTA以0.4 mL/min流速即可完全洗脱,富集倍数高达250倍。样品预富集后的火焰原子吸收光度法线性范围为0.5～1.2×104μg/L,r=0.999 2,检出限(3σ,n=11)为0.04μg/L。利用功能介孔材料分离富集水样中痕量铅离子,用火焰原子吸收法测定含量,相对标准偏差(RSD)小于等于3%(n=6),回收率在98.2%～99.1%之间。

The determination of trace amount of lead ions in water by FAAS after preconcentration with imprinting of functional mesoporous silica

Molecular imprinting functional mesoporous silica was prepared by using lead ion as a template and 2-mercaptobenzothiazole as a modification agent.The material was characterized by scanning electron microscopy(SEM) and FT-IR.It was found that the functional material had selective affinity for lead ions,it could be easily separated from Cu(Ⅱ),Cd(Ⅱ) and Hg(Ⅱ) and its maximum capacity was 0.64 mmol/g.When it was made into minicolumn to preconcentrate trace amount of lead ions in water,the saturated column could be eluted by 2 mL of EDTA(0.5 mol/L) and the preconcentration factor was 250.After preconcentration,the linear range of FAAS for Pb(II) was 0.5～ 1.2×104 μg/L with a correlation coefficient of 0.9992 and the detection limit(3σ,n=11) was 0.04 μg/L.The molecular imprinting functional mesoporous silica was utilized to preconcentrate trace amount of lead ions in river,the relative standard deviation(RSD) of FAAS for six replicate analyses was better than 3%,and the recoveries were between 98.2% and 99.1%.The results are satisfactory.