Sensitive and rapid biosensor for the determination of rhamnose based on the catalytic effect of the oxidation of calcein by H2O2

Abstract

We report a new catalytic biosensor for the detection of rhamnose (Rha) based on combining the high sensitivity of a fluorescence method with the high selectivity of a catalytic reaction. The biosensor has the advantages of high sensitivity (limit of detection 1.9 × 10⁻¹⁷ g mL⁻¹) and selectivity; it is non-radioactive, non-invasive and safe to use. The biosensor was used to determine trace amounts of Rha in cigarettes and jujubes and the results were in good agreement with those obtained by high-performance liquid chromatography. Calcein (R)-Rha was also determined by high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance. We also report the mechanism used in the catalytic biosensor for the determination of trace amounts of Rha.