“…A chapter on QA in environmental analysis (Cofino 1993) covers total quality management of environmental information, quality systems for chemical analysis, QA in the laboratory (organization, management, methodology validation, quality assessment) and interlaboratory studies. The review by Tölg and Tschöpel (1994) on systematic errors in trace analysis is an excellent one by a wellrespected trace analytical researcher and colleague. It includes systematic errors and their avoidance, from various sources and steps in the analytical procedure such as sampling, sample storage, pretreatment, decomposition and separation, volatilization, adsorption, blanks, contamination, alteration of valency state; basic rules for the recognition and elimination of systematic errors are given.…”