High-efficiency extraction of nucleosides based on the combination of self-assembly ionic liquid layer and boronic acid-functionalized attapulgite.

Boronate affinity materials have been widely used for selective capture of cis-diol-containing molecules, but most do not have sufficient extraction efficiency. We have prepared boronic acid-functionalized attapulgite, and then it was coated with imidazolium-based ionic liquid, 1-dodecyl-3-methylimidazolium bromide (C12mimBr), via physical self-assembly process. The extraction efficiency of the material increased dramatically after coated with C12mimBr, and its enrichment ratios for nucleosides increased by 9- to 282-fold. Besides, the C12mimBr-coated adsorbent did not lose selectivity and was able to capture cis-diols in the presence of a 100-fold excess of interferences. C12mimBr-coated material was applied to selective enrichment of nucleosides from human urine. The limits of detection and the limits of quantification were in the range of 0.06-0.46ngmL(-1) and 0.20-1.53ngmL(-1), respectively. Reproducibility of the method was determined with relative standard deviations≤9.9%. The recoveries of the target nucleosides from spiked human urine were in the range of 87.8-109.6%. In our preception, self-assembly ionic liquid layer can serve as a promising alternative to improve the extraction efficiency of boronate affinity materials.