A hybrid material was prepared from graphene oxide and melamine sponge, and modified with phenylboronic acid to obtain a sorbent for the enrichment of the nucleosides cytidine, uridine, inosine, guanosine and adenosine. The loading capacity typically is around 27.8 mg g-1 which is comparable to other sorbents, and highly selectivity for cis-diols is observed even if the concentration of potential interferents is 1500-fold higher. The sorbent was placed in an injector, and the process was operated semiautomatically by using a peristaltic pump. The sorbent is stable and can be re-used six times without decrease in efficiency. It was applied to the selective extraction of the cis-diols (cytidine, uridine, inosine, guanosine, adenosine) from HepG2 cells. It presents good linear between 3 to 5000 μg L-1 and the limits of detection (in HPLC analysis with UV detection) are 1-4 μg L-1. Good recoveries of 85-101% were obtained with spiked HepG2 cells samples, with relative standard deviation of ≤9.9%. Graphical abstract Schematic for the preparation of boronic acid modified graphene oxide/melamine sponge composite for in-syringe solid-phase extraction of nucleosides.
Keywords: Boronate affinity materials; Gold nanoparticles; HepG2 cells; Isotherms; Peristaltic pump; Surface area; Surface morphology; Syringe.