A new “off–on” fluorescent probe for Al3+ in aqueous solution based on rhodamine B and its application to bioimaging

In this paper, a new fluorescent probe has been synthesized and applied as “off–on” sensor for the detection of Al 3+ with a high sensitivity and excellent selectivity in aqueous media. The sensor was easily prepared by one step reaction between rhodamine B hydrazide and pyridoxal hydrochloride named RBP. The structure of the sensor has been characterized by nuclear magnetic resonance and electron spray ionization-mass spectrometry. The fluorescence intensity and absorbance for the sensor showed a good linearity with the concentration of Al 3+ in the range of 0–12.5   μM and 8–44   μM, respectively, with detection limits of 0.23   μM and 1.90   μM. The sensor RBP was preliminarily applied to the determination of Al 3+ in water samples from the lake of Henan University and tap water with satisfying results. Moreover, it can be used as a bioimaging reagent for imaging of Al 3+ in living cells.