Efficient detection of geosmin and 2-methylisoborneol in natural/drinking water by UIO66-NH2 composite-derived porous carbon

Solid-phase microextraction (SPME) has been widely used for the analyzing trace organic pollutants in environmental samples. The properties of coatings have a significant effect on the application range, selectivity and sensitivity of existing analytical methods. Therefore, the development of SPME technology depends on fibers with a stable, efficient, and selective coating. In this study, metal-organic frameworks (MOFs) were used to fabricate porous carbon membranes in situ for SPME. The composite material (UIO66-NH2@PAC) was directly carbonized to prepare a derivative porous carbon material (C-UIO66-NH2@PAC), which was applied to the extraction of off-odour organic pollutants for the first time. The Zr-N co-doping in the material was not only beneficial to the formation of derivatized porous carbon, but also endowed it with a certain hydrophilicity, which was highly advantageous for capturing weakly polar compounds. By optimizing the extraction and desorption conditions, a highly selective and sensitive analytical method was developed, which exhibited a detection limit of 0.61 and 0.78 ng L-1 for 2-methylisoborneol (2-MIB) and geosmin (GSM), respectively, along with a linear range from 10 to 3000 ng L-1. Both intra-fiber repeatability (RSD 5.5% and 3.7%) and inter-fiber repeatability (RSD 9.7% and 8.8%) were satisfactory. The fiber coated with C-UIO66-NH2@PAC exhibited high extraction efficiency (the extraction efficiency of the analytes was 4.6-8.3 times higher than that of commercial fibers), and had excellent thermal and chemical stability. Finally, the C-UIO66-NH2@PAC-coated fibers were successfully applied to the SPME analysis of off-odour organic pollutants in real water samples, and these results highlighted the broad prospect for the detection of natural/drinking water.