The role of analytical chemistry in process quality control

The growing need for quality supervision and control in production processes is briefly outlined. After a summary of available process analytical devices, and a short discussion of their possibilities and limitations, an alternative approach is discussed. This approach is based on the development of a dynamic process model which allows on-line quality predictions to be made by means of so- called state estimators. The advantage is that it becomes possible to use quantities which give only indirect information about the product quality, but which are more readily accessible for continuous or on-line monitoring in earlier stages of the process.