Figure 1: The influence of pH of the aqueous phase in the formation and extraction of the complrx of manganese (II) with Phen and oNBASA, (CMn=2.23 × 10-5 M, CPhen=2 × 10-4 M, CoNBASA=1.5 × 10-4 M, KFK-3, λ=400 nm).