Reversed-phase chromatography in extended-nano space for the separation of amino acids

In this work we used reversed-phase chromatography in extended-nano channels to separate amino acids. A hydrophobic surface modification of extended-nano channels was established. A sample mixture of fluorescein and sulforhodamine B (0.5 and 0.05 mM respectively) was used for the demonstration of a reversed-phase separation mode. A small amount of sample band (30 fL) was injected into the separation channel, and two compounds were successfully separated. The maximum theoretical plate number of sulforhodamine B was 300,000 plates/m. Two sets of 3 amino acids (3.75 mM each) were separated using 0.01 M citrate buffer (pH 5.5) with 0.01 M sodium perchlorate and 12 and 25% of acetonitrile as a mobile phase. A successful separation (320,000 plates/m with plate height of 3.2 μm for serine) was accomplished.