[Study on the determination of trace metals in complex matrices by chelation ion chromatography]

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 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 microgram/L level. The method has been systematically applied in rock, alloy, soil, plant and animal samples.