螯合离子色谱法分析复杂基体中痕量金属离子的研究

Study on the Determination of Trace Metals in Complex Matrices by Chelation Ion Chromatography

发展了应用螯合离子色谱法分析复杂基体中痕量金属离子的新方法。针对不同的检测目的，利用螯合柱（ＭｅｔＰａｃＣＣ－１）和浓缩柱（ＴＭＣ－１），采用适当的洗脱液在线将基体中的阴离子、一价阳离子、碱土金属离子以及其它干扰离子除去，同时，浓缩富集待测的痕量金属离子，然后再选择适当的梯度淋洗体系，在含有双功能基的分析柱上分离Ｐｂ，Ｃｕ，Ｃｄ，Ｃｏ，Ｚｎ和Ｎｉ等过渡金属离子和１４种镧系金属离子，继而用在线柱后衍生和光度法检测。方法简单快速，样品经适当的酸消解成溶液后即可进样，灵敏度高，检测限为１０－９级甚至更低，已应用于矿石、合金、土壤、作物以及生化等样品的测定。

In this paper, a new method for determination of trace metal ions in complex matrices by chelation ion chromatography has been developed. In accordance to different analysis purpose, different interference should be selectively eliminated. On the chelating resins, all anions, alkali and alkaline earth metals could be eluted by ammonium acetate eluent (pH 5.5), tervalent cations could be eluted by pyrophosphoric acid/ammonium acetate eluent (pH 5.5). On sulfonated cation exchanger, heavy metals, transition metals, iron and aluminum could be eluted by hydrochloric acid/ethanol and oxalic acid/nitric acid eluents. Then, the concentrated lanthanides and transition metals (Pb, Cu, Cd, Ni, Zn and Co) were separated on bifunctional ion exchange column by a proper concentration gradient of eluents, coupled with post column spectrophotometric detection. Test samples could be injected directly into the column for analysis after the sample digestion. The detection limits of the method (signal to noise=3∶1) were at or below μg/L level. The method has been systematically applied in rock, alloy, soil, plant and animal samples.