[Parameters of the liquid-liquid extraction of toxicologically relevant organic compounds. Part 1: Methodology of the experimental determination of partition constants and pH-dependent partition quotients; results obtained with acidic compounds].

Though liquid-liquid extraction is most widely used technique for isolating organic compounds (drugs, poisons), its fundamental parameters (partition constants and dissociation constants) are not determined explicitly in most cases; they are mostly estimated indirectly together with other factors in the form of resultants (total yield, detection sensitivities). For this reason we determined the partition quotients and their pH-dependence for more than 300 slightly volatile organic compounds (mainly drugs) in two-phase systems (aqueous buffer solution/solvent non-miscible with water). Nearly all the determinations were performed using diethyl ether and chloroform; other organic solvents were applied especially in studying slightly extractable compounds. The results obtained with 63 acidic compounds are reported.