Boronate affinity adsorption of cis-diol-containing biomolecules in nonaqueous solvent.

Boronate affinity has attracted much attention in recent years. It has been broadly used for selective isolation and enrichment of cis-diol-containing molecules. Conventionally, the cis-diols are adsorbed in mild alkaline aqueous solutions. In this work, for the first time, we found that boronate affinity adsorption could also be performed in nonaqueous solvent at nonbasic pH. Cis-diol-containing compounds present in herbal medicines were used for the adsorption test. The results indicated that all compounds obtained higher recoveries in the organic solvents (methanol, acetonitrile, ethyl acetate) compared with alkaline buffer. The adsorption of vicinal cis-diol-containing molecules in organic solvents could be accomplished rapidly, with high selectivity and high recoveries (>80%). These results shed light on the possibility of boronate affinity adsorption in nonaqueous solvents. The results are very important for the isolation and enrichment of cis-diols, which have poor solubility in water, especially for those in herbal medicines.