IMPACT OF STORAGE AND FILTER MATERIALS ON THE RECOVERY OF 43 ORGANIC MICROPOLLUTANTS

Organic micropollutants are frequently detected in the aquatic environment. Therefore, a large number of field and laboratory studies have been conducted in order to study their fate in the environment. Due to the diversity of chemical properties among these compounds it can be assumed that some of them may interact with materials commonly used in field and laboratory studies like tubes, filters, or sample bottles. The aim of our experiments was to study the interaction between those materials and a solution with 43 widely used basic, neutral, and acidic organic micropollutants hereby covering a broad range of polarities. Experiments were conducted with spiked tap water for the materials as batch study (up to 28 days) and for different syringe filters by filtration with subsequent fraction collection.

For most of the laboratory materials tested, no significant loss of micropollutants was observed. Best recoveries over a wide range of organic compounds were observed for batches in contact with the materials (in descending order) acryl glass, PTFE, HDPE (from Nalgene^©), and PP. The use of Pharmed^©, silicone, NBR70, Tygon^©, and LDPE should be avoided. Especially soft tubing material influences many analytes. In general, anionic micropollutants were least influenced by contact with different materials during storage.

Filtration with most of the tested filter types lead to no significant loss of almost all of the investigated micropollutants. One of the reasons could be that the contact time is to too short for sorption of the analytes to the surfaces of the filter materials. Nevertheless, some few substances (Loratadine, Fluoxetine, Sertraline, and Diuron) were sorbed significantly during the first mL of the filter process. The poor recovery of these substances can be improved by discarding the first 25 mL (or as much as possible) to fill the sorption places on the filter material before actually starting sampling.