TY - JOUR T1 - Application Cloud Point Extraction Method Joined with Liquid Ion Exchange for Selective Determination of Fe³⁺ and Hg²⁺max = 450 nm, the ion pair association complex of Fe³⁺ λ_max= 477 nm but for Hg²⁺ λ_max= 476 nm, so that, the optimum condition for high extraction efficiency was 0.5M HCl for both ions ,100 μg metal ions in 10 mL aqueous solution 1×10^-4 M of HPBN and necessary to heating the solution at 90°C for 20 min to Fe³⁺ ion and 15 min. For Hg²⁺ ion and in presence of 0.5 mL Triton X-100 for Fe³⁺ and 0.8 mL Triton X-100 for Hg²⁺ ion. As well as the research involved other studies such as electrolyte effect interferences effect, stoichiometry, application and determination of trace amounts of Fe(III) and Hg(II) in environmental sample by spectrophotometry. ER -