Analytical chemistry is increasingly becoming an important basis for decision making in science, economy, trade, health care, environmental and consumer protection, sports and jurisdiction. In all spheres, analytical results need to fulfill a purpose. This means being accurate to a specified extent according to the required level of uncertainty, as well as being comparable, depending on the range of validity. In many cases, this range is global. Reference ma terials are important tools for meeting these demands. Driving forces behind the increasing diversification of reference materials also include the rapid development of analytical chemistry, the development of new methods and applications, and the inclusion of new analytes, matrices and materials. The growing need for reference materials is giving rise to an increasing demand for information, orientation and stimulation. Laboratory staff have questions on calibration, validation, home-made reference materials and certified reference materials. This book is a handbook for analytical chemists and technical per sonnel in analytical laboratories, where it should become a standard reference work. Berlin, February 2000 A. Zschunke Contents 1 Introduction Adolf Zschunke 1. 1 Analytical Thinking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2 Demands on Analytical Chemistry. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 3 Measures Designed to Build Confidence . . . . . . . . . . . . . . . . . . . . . . . 6 1. 4 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 Classification of Reference Materials Werner Hiisselbarth 2. 1 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 10 2. 2 Physical Character . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2. 3 Supplied Property. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 . . . . . . . . . . . 2. 4 Metrological Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 . . . . . . 2. 5 Preparation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 . . . . . . . . . . 2. 6 Intended Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. 7 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .