A three-dimensional nitrogen-rich conjugated microporous polymer for solid-phase microextraction of nitroaromatic compounds from environmental water and soil samples.

Nitroaromatic compounds (NACs), as a kind of important chemical intermediates, are widely used in industrial productions. However, NACs have carcinogenic effect and their residues may pose harm to human health. Therefore, there is necessity to set up effective analytical method to monitor them in some environmental samples. However, because of their low concentrations in real samples, they need to be enriched by an effective adsorbent before the subsequent instrumental detection. In this work, a three-dimensional nitrogen-rich conjugated microporous polymer (DCT-Try-CMP) was synthesized with 3,6-dichloro-1,2,4,5-tetrazine and triptycene as monomers via Friedel-Crafts reaction. It presented a good adsorption capability for the NACs. After optimization, a solid-phase microextraction with DCT-Try-CMP fiber combined with gas chromatography-flame ionization detection for the quantitation of trace NACs in environmental water and soil samples was developed. The limits of detection of the method (S/N = 3) for environmental water and soil samples were 0.08-0.30 μg L and 1.00-5.00 ng g, and the limits of quantification (S/N = 9) were 0.27-0.90 μg L and 3.00-15.0 ng g, respectively. The linear quantification response ranges for the analytes were 0.27-200 μg L and 3.00-1000 ng g for water and soil samples, respectively. For water samples at the analytes concentrations of 5.00, 50.0 and 100 μg L, the method recoveries ranged from 82.2 % to 120 % and for soil samples at the concentrations of 15.0, 200 and 400 ng g, the method recoveries fell in the range from 80.2 % to 120 %. The method provides a sensitive and effective approach for monitoring trace NACs in environmental water and soil samples.