A graphene oxide functionalized with 3-aminophenylboronic acid for the selective enrichment of nucleosides, and their separation by capillary electrophoresis

We show that graphene oxide functionalized with 3-aminophenylboronic acid represents a useful new adsorbent for the selective enrichment of the nucleosides, adenosine, guanosine, uridine, and inosine, which then were quantified by capillary electrophoresis. The analytes were separated within 10 min using a borate buffer of pH 9.3 (containing sodium dodecyl sulfate) at an operating voltage of 25 kV, a temperature of 20 A degrees C, a sample injection time of 5 s, and with UV detection at 254 nm. The effects of sample pH, sample flow rate, eluent type, and eluent flow rate were optimized. Under the optimized conditions, the enrichment factor was determined to be 10. A linear relationship was obtained over the 0.1 to 100 mu g mL(-1) concentration range, with regression coefficients of > 0.9991. The intra-day and inter-day relative standard deviations of this method were in the range of 3.1-5.0 % and 4.8-7.5 %, respectively. The method was applied to the determination of the nucleosides in (spiked) traditional Chinese medicine injection samples, and recoveries ranged from 70.8 to 106.7 %.