CHEMICAL SPECIATION OF AMINO-ACIDS IN ELECTROLYTE-SOLUTIONS CONTAINING MAJOR COMPONENTS OF NATURAL FLUIDS

Protonation constants of glycine, DL alpha-alanine, L(-)histidine, L()lysine, L(-)serine, iminodiacetic, L(+)aspartic, and L(+)glutamic aci ds, in aqueous NaCl, MgCl2, CaCl2, (C2H5)(4)NI and Na2SO4 solutions ha ve been determined in different temperature-ionic strength conditions (1 atm pressure), using the pH-metric technique. The differences in pr otonation constants determined in different salt solutions were explai ned using a complex formation model. Particular attention has been pai d to obtaining thermodynamic formation data for natural conditions, su ch as that of seawater. A general model for the weak interactions betw een amino acids and alkali and alkaline earth chlorides and sulfates i s discussed.