Simultaneous determination of heavy and transition metals in biological samples by chelation ion chromatography

A highly sensitive method of simultaneous separation and determination of P b2+, Cu2+, Cd2+, Co2+, and Ni2+ was developed and evaluated by on-line samp le pretreatment of chelation ion chromatography. Bulk quantities of anions, alkali metals, alkaline earth metals, tervalence cations, and other interf ering components were eliminated by pyrophosphoric acid / ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on im inodiacetate-based resins. Then, they were disabsorbed and transferred to s ulfonated cation exchangers. Finally, the concentrated trace metals were separated on a bifunctional ion exchange column by a concentration gradient of oxalic acid and sodium nitr ate 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 mu g L-1 le vels. This technique was validated by analyzing standard biological referen ces.