A fluorescence turn-on assay for simple and sensitive determination of hemin and blood stains

•A simple and sensitive fluorescence assay has been developed for detection of hemin and blood stains.•This method is based on a novel dihydrofluorescein with great sensitivity toward reactive radical species generated by hemin/peroxides.•This assay exhibits great selectively and sensitivity for hemin with detection limits at picomolar levels.•A portable test strip has been prepared, which worked very well for convenient naked-eye detection of hemin and blood stains.