Boronic acid grafted metal-organic framework for selective enrichment of cis-diol-containing compounds

Abstract

This study constructed boronic acid grafted Zr-MOF (BA-Zr-MOF) by a simple pre-installation strategy through mixed organic ligands. Typically, BA-Zr-MOF was prepared by one-step hydrothermal method used for enrichment of cis-diol-containing nucleosides through pipette tip solid-phase extraction (PT-SPE) followed by detection of high-performance liquid chromatography. It is worth mentioning that BA is well assembled into MOF and cis-diol-containing compounds can be efficiently and selectively enriched by abundant boronic acid groups. Three groups of different types of compounds were used to evaluate their selectivity and the results showed the excellent selectivity to cis-diol-containing compounds of as-prepared adsorbent. The BA-Zr-MOF adsorbent possesses a high adsorption capacity, which can reach 86.40 mg g−1 for adenosine. Under the optimal extraction condition, a PT-SPE-HPLC method based on BA-Zr-MOF for analysis of nucleosides was established. The linear range of the four nucleosides is 0.01 to 50 µg mL−1 with R2 ≥ 0.99 and the detection limits (LODs) are estimated at between 0.005-0.012 µg mL−1. The recoveries in urine were used to test the reliability of the analytical methods, which ranged from 82.8% to 117.1%, with intra-day relative standard deviations (RSDs) ranged from 0.1% to 4.2% and the inter-day RSDs ranged from 0.2% to 6.2%. All the results show that the pre-installation strategy based on dual ligands is an alternative to fabricate MOF composite material and BA-Zr-MOF is a promising material for the analysis of cis-diol-containing biomolecules.