Use of ion chromatography for the determination of heavy and transition metals in biochemical samples

A novel, highly sensitive method for simultaneous separation and determination of Cu 2+, Ni 2+, Zn 2+, Cd 2+, Co 2+, Mn 2+ and Pb 2+ in biochemical samples was developed and evaluated by ion chromatography. All of these metals were well separated on a bifunctional ion-exchange column by a concentration gradient of oxalic acid and sodium chloride eluents, coupled with spectrophotometric detection after post-column derivatization with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol at 560 nm. The method detection limits (signal-to-noise 3:1) were at μg l −1 levels. The calibration graphs were linear ( r 2>0.999) over two-orders of magnitude. This technique was optimized and validated by analyzing five standard biochemical references.