These Conference Proceedings deal with the papers presented at the International Conference on Ion Exchange Processes (ION-EX '90) which was held at The North East Wales Institute of Higher Education, 9- 11 July 1990. The camera-ready paper format was chosen so that delegates could receive their copy on arrival at the Conference. The Proceedings include reviews of biological materials, inorganic ion exchangers, the nuclear industry, theoretical aspects and new advances. In addition, there are research papers dealing with industrial ion exchange procedures and new materials. The Proceedings should therefore be of interest to those who need to be brought up to date in the various aspects of processes which involve ion exchange and ion chromatography which are now accepted as important in analysis, separation processes and process control. In each of these areas there have been important developments which are herein described. As Editors we should like to express our thanks to the individual authors for preparing their manuscripts in the required format and to Haydn Hughes and Linda Sneddon for their invaluable assistance in compiling these Proceedings. PETER A. WILLIAMS MICHAEL J. HUDSON V1 CONTENTS v Preface Part 1: Biological Materials The Importance of Ion Exchange Processes in Living Systems 3 R. J. P. Williams The Use of Chemically Suppressed Ion Chromatography in Elemental Analysis 17 J. P. Senior Biological Separations Using Latex-Based Pellicular Resins 23 K.