聚丙烯腈微球预富集分离微柱与FAAS联用测定痕量Cd(Ⅱ)和Zn(Ⅱ)

Determination of trace Cd(Ⅱ) and Zn(Ⅱ) on a micro-column filled with polyacrylonitrile coupled with flame atomic absorption spectrometry

将自制的聚合物微球填充到玻璃柱制备了2.5cm×4 mm i.d.预富集分离柱,并将其与火焰原子吸收光谱(FAAS)法联用,测定了其对Cd2+和Zn2+的动态吸附,建立了测定溶液中痕量Cd2+和Zn2+的预富集分离-FAAS方法;优化了对Cd2+和Zn2+的吸附富集与洗脱条件,在室温下,溶液pH为5～6,上样和洗脱液流速分别为6.0 mL/min和3.0 mL/min,上样和洗脱时间分别为10 min和1 min时,动态吸附量分别达到47.6 mg/g和39.3 mg/g;检出限分别为1.06μg/L和0.855μg/L;相对标准偏差(RSD)分别为2.6%和1.8%。将本方法试用于地下水、地表水和土壤中痕量镉和锌离子的测定,得到加标回收率分别为94.0%～102.6%和94.6%～100.4%。

In this paper,the adsorption properties of Cd2＋ and Zn2＋ on the micro-column（2.5cm×4 mm i.d） filled with polyacrylonitrile microsphere as the adsorption material synthesized by ourselves were studied by flame atomic absorption spectrometry.The Adsorption conditions f Cd2＋ and Zn2＋ on the column such as pH,flow rate and time et al were optimized.The results showed that at the room temperature,pH of solution was 5～6,the flow rate and time of loading sample were 6 mL/min,and 10 min and the eluant 3.0 mL/min and 1 min respectively.The as-prepared micro-column had excellent adsorption properties and high adsorption capacities for Cd2＋ and Zn2＋ which reached 47.6 and 39.3 mg/g respectively.0.50 mol/L chloride acid showed the best desorption property and the recovery reached 99%.The detection limits（3σ,n=10） were 1.06 and 0.855 μg/L with the relative standard deviations（RSDs） of 2.6 and 1.8% respectively.This method was applied to the determination of trace cadmium and zinc from environmental samples,the recoveries were in the range of 94.0%～102.6% and 94.6%～100.4% respectively.