离子液体萃取-火焰原子吸收光谱法测定地表水中微量锌

合成了离子液体1-丁基-3-甲基咪唑六氟磷酸盐(Bmim]PF6),并将其用于水样中锌的萃取。在500 mL水样中依次加入10 g.L-1EDTA溶液3 mL和离子液体5 mL,在pH 7左右的条件下振摇5 min,分出离子液体相,用1.0 mol.L-1盐酸溶液10 mL返萃取,于水相中火焰原子吸收光谱法测定其锌量。锌的质量浓度在0.005～0.02 mg.L-1范围内与吸光度呈线性关系,方法的检出限(3σ)为0.75μg.L-1。应用此法测定地表水中锌,回收率在85%～110%之间。

FAAS Determination of Micro-amount of Zinc in Ground Surface Water after Extraction with Ionic Liquid

An ionic liquid,1-butyl-3-methylimidazolium hexafluorophosphate(PF6),was synthesized,and used to extract Zn(Ⅱ) from water sample.Three mL of 10 g·L-1 EDTA solution and 5 mL of the ionic liquid were added to 500 mL of water sample,and the mixture was shaked for 5 min.The ionic liquid phase was separated and back extracted with 10 mL of 1.0 mol·L-1 HCl,in which the Zn(Ⅱ) content was determined by FAAS.Linear relationship between values of absorbance and mass concentration of zinc was obtained in the range of 0.005-0.02 mg·L-1,with detection limit(3σ) of 0.75 μg·L-1.The proposed method was used in the analysis of surface water,giving values of recovery in the range of 85%-110%.