the preconcentration and determination of pb2+, cu2+, co2+, ni2+, fe2+ and zn2+ elements in water samples using citrate form of anion-exchange resin

lead, copper, cobalt, nickel, iron and zinc ions form monocitrate complexes (negative charge) in citrate solution which is absorbed on the citrate form of anion-exchange resins (citrate as counter ion) y exchange of citrate ion with citrate complexes. these are subsequently recovered from the resin by 0.5m ammonium citrate eluent at ph 2.0. under optimized conditions, quantitative recovery was achieved simultaneously for lead, cobalt, copper, nickel, iron and zinc (preconcentration factor 20). each element could be determined by atomic absorption spectroscopy (aas) with high precision.