SIMULTANEOUS DETERMINATION OF ZINC(II) AND IRON(III) IN HUMAN SERUM BY LIQUID-CHROMATOGRAPHY USING POSTCOLUMN DERIVATIZATION WITH 4-(2-PYRIDYLAZO)-RESORCINOL

A liquid chromatographic method for the determination of sub-mu g/ml, levels of zinc(II) and iron(III) in human serum has been studied by us e of a post-column derivatization with 4-(2-pyridylazo)-resorcinol (PA R) as a chelating agent. Human serum samples are pretreated with hydro chloric acid and trichloroacetic acid for deproteination, and then sod ium acetate solution is added for adjusting the pH of the aqueous samp le to 3.5. The sample is injected onto a 10 mu m bonded phase, strong- acid ion exchange column, and eluted with 0.340 mol/L tartrate buffer (pH 3.75) at a flow rate of 1.0 mL/min. The eluate is mixed with 10(-4 ) mol/L PAR solution as the post-column reactant at the same now-rate of the elution of the metal ions at 30 degrees C, and the absorbance o f the mixed solution is monitored at 515 nm (Zn) and 715 nm (Fe). The human serum samples can be analyzed with good precision by the propose d method.