New systems are described for the highly efficient solvent extraction of mercury with high-molecular-weight amines from aqueous iodide or bromide solutions. Mercury extracts essentially quantitatively at both the sub-nanogram and macro levels. The quaternary amines are especially attractive because of their ability to extract mercury from alkaline as well as acidic solutions. Regeneration of the amine solvent is readily achieved by stripping the mercury with alkaline solutions of cysteine.