Fluorine-bearing covalent organic framework as an efficient solid-phase extraction adsorbent for the analysis of triazines and 6PPD-quinone in run-off waters

The urban environment is a source of a wide variety of contaminants, which ultimately run-off or leach into water streams. Triazine herbicides have been extensively used in urban landscape management, leaving behind residues of both the parent chemicals and several degradation products. Another dangerous chemical frequently detected in run-off waters is the tire-wear compound 6PPD-quinone, derived from heavy traffic and use of recycled rubber products. Monitoring of these contaminants in water is enforced by EU legislation, therefore, the development of efficient solid-phase extraction adsorbents is of high importance. Covalent organic frameworks (COFs) have attracted considerable interest in the recent years as adsorbents for sample preparation due to their large surface area and the possibility of tailoring their chemical features and pore size to adsorb specific environmental pollutants. Herein, we demonstrate that these materials can be employed to prepare efficient and readily applicable solid-phase extraction (SPE) cartridges to monitor nine triazines and 6PPD-quinone in urban run-off waters. Three COF derivatives were tested, and the COF amount, adsorption mechanism, as well as several performance parameters, such as recoveries, breakthrough volume, carry-over, and reusability were investigated. The fluorinated derivative TpBD-(CF 3 ) 2 showed good performance with average recoveries of 87.6%, enabling concentration factors from 200 to 1000-fold and ng/L limits of quantification. The performance was comparable to that of the commercial cartridges which contain larger adsorbent amounts, highlighting the potential of COFs for use in miniaturized monitoring devices.