DETERMINATION OF TRACE AMOUNTS OF IRON(II,III) IN NATURAL-WATER BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Trace amounts of iron(II,III) ions in natural water were determined by reversed-phase high-performance liquid chromatography (HPLC) using precolumn derivatization with 1-(2-pyridylazo)-2-naphthol (PAN). A good separation of PAN chelates with iron(II,III), nickel(II), and copper(II) ions was achieved with a chemically bonded ODS column using THF/H2O/methanol (30/50/20, v/v/v) containing 0.01 M tetrabutylammonium thiocyanate as eluent. The calibration graphs of iron(II), iron(III), nickel(II), and copper(II) ions were linear in the concentration range of 0-100 ng CM-3. The detection limits of iron(II), iron(III), nickel(II), and copper(II) ions were 6.19, 6.38, 6.72, and 8.45 ng cm-3 with relative standard deviations (n = 10) of 7.24, 6.63, 6.76, and 1.44% at a concentration level of 10 ng cm-3, respectively. It was demonstrated that the proposed HPLC method with PAN chelates is useful for the determination of heavy metal ions in natural water. (C) 1994 Academic Press, Inc.