A new high-performance chelation ion chromatographic system for the direct determination of trace transition metals in fuel ethanol

A new chelation ion chromatographic system for the determination of transition metals was developed. The isocratic separation of Fe2+, Fe3+ and Cu2+ simultaneously with Mn2+, Pb2+, Cd2+, Zn2+ and Ni2+ was obtained on an iminodiacetic acid (IDA) functionalized silica column 150 x 4.0 mm id. with an optimized eluent composed of 2.5 mmol L-1 dipicolinic acid, 10 mmol L-1 HCl and 60% v/v of methanol at flow rate of 0.5 mL min(-1). Post-column reaction with 4-(2-pyridylazo)resorcinol (PAR) was used for sensitive spectrophotometric detection at 510 nm of the separated metals at low ppb level. The applicability of the developed method to the analysis of fuel ethanol was demonstrated.