Elution of peptides using monolithic column containing GNPs. Condition: Column length 10 cm, concentration of peptide solution 0.1 mg/mL, injection volume 100 nL, mobile phase 0.1% (v/v) formic acid in aqueous 90% acetonitrile, flow rate 1 μL/min, UV detection at 214 nm. Traces: Tyr-Gly (1), Phe-Gly-Phe-Gly (2), Tyr-Gly-Gly-Phe-Leu (3), His-Cys-Lys-Phe-Trp-Trp (4).