Metal Complexes in Biology and Medicine

In coordinate compounds, knowledge of the stability constants of the complexes is necessary for preliminary quantitative treatment. Metal ions are fundamental elements for the maintenance of the life spans of humans, animals and plants and play an important role in biological systems. A recent technique involving the use of paper electrophoresis is described for the study of equilibria in binary complex systems in solution. This method is based on the movement of a spot of metal ion in an electric field at various pHs of background electrolyte. A graph of pH versus mobility gives the information for binary complexes and calculates their stability constants. The logarithm stability constants of the ML and ML2 complexes of norvaline were found to be (8.61 ± 0.03; 7.05 ± 0.07), (6.93 ± 0.05; 5.47 ± 0.03) and (4.57 ± 0.02; 3.00 ± 0.05) for the mercury(II), nickel(II) and lead(II) complexes, respectively at ionic strength 0.1 M perchloric acid and a temperature of 35°C.