天然水体中铜含量很低, 直接测定较为困难。 利用纳米氧化锌对Cu(Ⅱ)良好的吸附性能, 建立了纳米氧化锌富集分离, 石墨炉原子吸收光谱法测定水样中痕量铜的新方法。 研究了纳米氧化锌对Cu(Ⅱ)的吸附行为, 优化了吸附条件。 实验结果表明: pH 3～7时, 纳米氧化锌粉末对Cu(Ⅱ) 吸附率达95%以上, 且吸附速度快。 与文献报道的用于痕量元素富集的活性炭、 粉体纳米二氧化钛等吸附剂比较, 纳米氧化锌最突出的优点是富集后不需要脱附, 用酸溶解后即可用石墨炉原子吸收光谱、 电感耦合等离子体发射光谱测定溶液中被富集元素的含量, 因此方法简单、 快速; 与富集后不需脱附, 用酸溶解后又成为均匀胶体溶液的胶体纳米材料比较, 纳米氧化锌溶解后是真溶液, 黏度小, 基体效应小, 更加适用于石墨炉原子吸收光谱、 电感耦合等离子体发射光谱检测。 该方法简单快速, 检出限低(0.13 μg·L-1), 精密度好, 相对标准偏差(RSD)为2.2%, 用于实际水样中痕量Cu(Ⅱ) 检测, 其回收率为91.6%～92.6%; 用于国家水质环境标准样品铜的测定, 结果吻合。

The content of copper in natural water is very low, and direct determination is difficult. Therefore, it is very meaningful for the combination of efficient separation-enrichment technology and highly sensitive detection. Based on the high adsorption capacity of Cu(Ⅱ) onto nano-sized ZnO, a novel method by using nano-sized ZnO as adsorbent and graphite furnace atomic absorption spectrometry as determination means was in this work. The adsorption behaviors of Cu(Ⅱ) on nano-sized ZnO was studied. Effects of acidity, adsorption equilibrium time, adsorbent dosage and coexisting ions on adsorption rates were investigated. The results showed that the adsorption efficiency was above 95% in a pH range from 3.0 to 7.0. Compared with other adsorbents for trace element enrichment such as activated carbon, nano-sized TiO2 powder, the most prominent advantage is nano-sized ZnO precipitate with the concentrated element can directly dissolved in HCl solution without any filtration and desorption process can directly analyzed by graphite furnace atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry. Compared with colloid nano materials, nano-sized ZnO is the true solution after dissolving have small matrix effect and viscosity more suitable for graphite furnace atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry detection. The proposed method possesses low detection limit (0.13 μg·L-1) and good precision (RSD=2.2%). The recoveries for the analysis of environmental samples were in a rang of 91.6%～92.6% and the analysis results of certified materials were compellent by using the proposed method.