Single-point titration of metal ions and ligands by measuring change in pH

A single-point titration method is described for the determination of metal ions and ligands. The method is based on deprotonation of a ligand on complexation with a metal. The resultant change in pH is used to calculate the concentration of the analyte. The limits and advantages of the method are discussed. Four selected systems, Pb(2+)-HPO(2-)(4), Cu(2+)-HCO(-)(3), Cd(2+)-EDTA and Ni(2+)-ethylenediamine are used to demonstrate the validity of the equations. The method is applied to determination of total carbonate in serum.