Selective fluorescence detection of histamine based on ligand exchange mechanism and its application to biomonitoring

We report on a novel histamine monitoring method by using a fluorescent probe, a complex between Ni2+ and calcein, based on a ligand exchange mechanism. The fluorescence intensity of this probe, which has been reduced due to effective quenching by Ni2+ ion, increases drastically by an addition of histamine. Furthermore, the probe shows high selectivity toward histamine among the various neurotransmitters in 0.1 M phosphate buffer solution (pH 7.4). Biomonitoring studies to detect histamine released from RAW264 cells are successfully represented.