Separation and Transport of Lithium of 10-5 M in the Presence of Sodium Chloride Higher than 0.1 M

Lithium is an important element for lithium battery and clinical treatment of manic depression. Thus,rapid and accurate methods for the determination of lithium and its separation and collection of lithium in recycle are receiving a great concern. Because of the high concentrations of Na⁺ in sea water and blood, very high Li⁺/Na⁺ selectivity is required for the separation and determination of Li⁺ at concentration less than 10^-4 M (700 ppb) in a large excess of Na⁺. We report here the methods of separation, transport and determination of lithium as low as 10^-5 M (M=mol dm^-3) in the presence of Na⁺ more than 0.1 M by using a water-soluble octabromoporphyrin; H₂P^4-) synthesized in our laboratory.