A homogeneous label-free colorimetric sensing strategy for bleomycin (BLM) assay was developed on the basis of BLM enhanced Fe(II)–H2O2–ABTS reaction. Fe(II) exhibits a catalytic effect on H2O2-mediated oxidation of ABTS by Fenton chemistry. BLM·Fe(II) complex possessed a significantly higher catalytic ability than Fe(II) probably because of the further formation of more active “activated oxo-iron-bleomycin complex”. The present method was convenient without any complicated chemical synthesis, modification, or tedious experimental procedures. Analysis results can be seen with the naked eye and monitored by UV-vis spectra. The peak absorbance exhibits a linear relationship with BLM concentrations from 25 nM to 1 μM, and a detection limit of 16 nM can be achieved. The designed colorimetric strategy may provide a promising alternative for BLM detection in clinical samples.
