Determination and Use of Stability Constants

About this book

This book describes potentiometric methods for determining stability constants and explains how these constants can be used to describe metal ion speciation in complex environmental and biological systems. It also provides three original computer programs on a disk for calculating stability constants and for using stability constants to calculate concentrations of molecular species in solution. The author gives examples of calculations for simple metal chelates, for metal complexes of large organic molecules, and for mixtures containing several metal ions and complexing agents in aqueous solution. They also describe common errors in calculating stability constants and how to avoid them. This carefully revised second edition is now even more useful to the reader, and, in particular, to those who make use of the program disk. Each program has been revised to improve speed, control, and error trapping.

Contents

1 Introduction; 1.1 Stability Constants -- Early Work; 1.2 Recent Developments; 1.3 Historical Evolution of Computational Methods; 1.4 Purpose of This Book; 2 Equilibrium Constants, Protonation Constants, Formation Constants; 2.1 Concentration Constants and Activity Constants; 2.2 Conventions Employed for Expressing Equilibrium Constants; 2.3 Equilibrium Constants and Stability Constants for Ca(II)--EDTA; 2.4 Species Distribution Curves; 3 Experimental Methods for Measuring Equilibrium Constants; 3.1 Methods Available; 3.2 Potentiometric pH Measurements; 3.3 Displacement Methods; 3.4 pH and p[H]; 4 Experimental Procedure for Potentiometric p[H] Measurement of Metal Complex Equilibria; 4.1 Materials; 4.2 The Reaction Mixture; 4.3 Calibration of the Potentiometric Apparatus; 4.4 The Experimental Runs; 4.5 Computation of Stability Constants; 5 Common Errors and Their Elimination or Minimization; 5.1 Measurement Errors; 5.2 Calibration and Electrode Care; 5.3 Reagents; 5.4 Equilibrium Measurements; 5.5 Calculations; 5.6 Selection of the Model; 6 Examples of Stability Constant Determinations; 6.1 Iminodiacetic Acid (IDA); 6.2 Procedure for IDA; Calibration; Checking the electrode system; Initial data for IDA; Final calculation for IDA protonation constants; Lead(II)/IDA system; 6.3 C--Bistren; 6.4 Procedure for C--Bistren; CBT alone; Cu(II)/CBT system; Computation of Cu(II)/CBT stability constants; 6.5 Determination of Stability Constants in the Presence of Competing Ligands; 7 Macroscopic and Microscopic Constants; 7.1 Some Definitions and Concepts; 7.2 Ionization of Tyrosine; 7.3 Macroscopic and Microscopic Protonation Equilibria of DOPA; 7.4 General Comments and Conclusions; 8 Determination of Stability Constants and Species Concentration of Complex Systems; 8.1 A Mixed--Ligand Binuclear Dioxygen System; 8.2 Non--aqueous Solvents; 8.3 Complex Multicomponent Systems; 8.4 Equilibrium with Solid Phases; 8.5 Equilibrium Involving Hydrolytic Species; 8.6 Species Distributions of Hydroxo and Fluoro Complexes of Al(III); 9 Critical Stability Constants and Their Selection; 9.1 General Criteria; Essential experimental control; Selection of a constant from a number of reported values; Reliability of investigator; Single investigator; Bibliography; 9.2 Examples of Critical Data Selection; 9.3 Need for Additional Critical Constants; 10 Development of a Complete Critical Metal Complex Data Base; 10.1 Introduction; 10.2 Linear Stability Constant Correlations; 10.3 Estimation of Stability Constants Not Measured Experimentally; 10.4 Metal Speciation in Sea Water With and Without Added Ligands; Appendix I; Program PKAS; Appendix II; Program Best; Appendix III; Program SPE; Appendix IV; Scientific and Technical Fields Requiring Stability Data; Appendix V; Minimum Requirements

Customer Reviews