Organic contaminants in water - conceptual considerations for the production of liquid reference materials in support of the new water framework directive

The lack of suitable certified reference materials for the determination of organic pollutants in water has become a major problem within the framewor k of the now European water policy. This paper highlights approaches toward s the production of certified reference materials and their drawbacks. On the basis of experience gained from proficiency-testing schemes, analyti cal practice, and reference material production a new concept for the produ ction of liquid reference materials to be used in support of European legis lation is presented and discussed briefly. The concept is based on a standa rd-addition approach and the simulation of effects interfering with the ana lytical process by use of individual matrix constituents or matrix-mimickin g substances in combination with water-miscible solvents. The concept enabl es quantification of dissolved organic compounds in unknown water samples a nd evaluation of the analytical process with the help of a reconstituted sa mple. Open questions for further research are also outlined.