A porous phosphate-rich β-cyclodextrin polymer for efficient and broad-spectrum enrichment of antibiotics

The contamination of surface and ground water by antibiotics has become a pressing environmental concern worldwide. However, the diversified physicochemical properities of antibiotics across different classes impart the major challenge for their broad-spectrum monitoring.

Herein, a novel phosphate-rich β-cyclodextrin porous crosslinked polymer named PCD-PCP is successfully synthesized prepared and used for highly efficient extraction of broad-spectrum antibiotics across six classes, covering a wide polarity range spanning over 10 orders of magnitude of logK_ow values. The PCD-PCP-coated thin-film microextraction (TFME) devices achieved significantly higher enrichment factors to all the six classes of antibiotics compared to commercial HLB coatings. By using the PCD-PCP-coated thin-films for enrichment, an ultra-sensitive TFME-HPLC-MS/MS method is established to simultaneously quantify 18 antibiotics, and the detection limits are all lower than the restricted limits in drinking water set by US EPA. Furthermore, the comprehensive analysis of density functional theory results suggests that the electrostatic attraction, hydrogen bonding, and van der Waals interactions jointly promote the extraction affinities.

This study not only provides profound mechanistic insights into the interactions between the adsorbent and antibiotics, but also offers a highly sensitive analytical method for the broad-spectrum enrichment of antibiotics in environmental water samples.