SIMULTANEOUS DETERMINATION OF HEAVY AND TRANSITION METALS IN BIOLOGICAL SAMPLES BY CHELATION ION CHROMATOGRAPHY

Abstract

A highly sensitive method of simultaneous separation and determination of Pb²⁺, Cu²⁺, Cd²⁺, Co²⁺, and Ni²⁺ was developed and evaluated by on-line sample pretreatment of chelation ion chromatography. Bulk quantities of anions, alkali metals, alkaline earth metals, tervalence cations, and other interfering components were eliminated by pyrophosphoric acid / ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on iminodiacetate-based resins. Then, they were disabsorbed and transferred to sulfonated cation exchangers.

Finally, the concentrated trace metals were separated on a bifunctional ion exchange column by a concentration gradient of oxalic acid and sodium nitrate eluents, coupled with post-column sepectrophotometric detection with 2-[(5-bromo-2-pyridyl)-azo]-5-diethyl-aminophenol (5-Br-PADAP) at 560 nm. The method detection limits (signal-to-noise 3:1) were at or below μg L⁻¹ levels. This technique was validated by analyzing standard biological references.

Acknowledgments