Systemtheorie in der Analytik

International agreements, which partly have become law already, and the demand for uniformity and comparability of analytical informations make it necessary to redetermine certain definitions and designations in chemical analysis. Units and ranges of quantity (working range, ranges of sample quantity and content) are defined and denominated, aiming at a system which is logical in itself and also leads to optimum solutions of analytical problems. The relations between the defined ranges, recommendations for denomination of methods, the problems of statements in ppm and ppb as well as the useless statement of 0% as begin of a range for measurements are discussed. Conversion relations for content systems are given.