Tryptophan capped gold–silver bimetallic nanoclusters-based turn-off fluorescence sensor for the determination of histamine

Tryptophan capped gold-silver bimetallic nanoclusters (Trp-Au/Ag BNCs) based turn-off fluorescence sensor has been developed for the simple and rapid determination of histamine. Sensor parameters such as the effect of solvent, irradiation time etc. were optimized and further studies were done using these results. Fluorescence quenching of BNCs happens with the incremental addition of histamine. This might be due to the aggregation of BNCs induced by the electrostatic force of attraction between the negatively charged BNCs and amino functional groups of histamine. The sensor showed good sensitivity for the determination of histamine with a linear range of 8.5 × 10−5 M to 4.0 × 10−6 M and a limit of detection (LOD) of 9.0 × 10−7 M. Practical utility of the proposed sensor has been proved through spike recovery analysis in synthetic physiological fluids. [Display omitted] •Quenching in fluorescence intensity of tryptophan capped gold-silver bimetallic nanoclusters (Trp-Au/Ag BNCs) by histamine.•First reported turn off fluorescence sensing of histamine by bimetallic nanoclusters.•Aggregation-induced fluorescence quenching of the BNCs by the analyte occurred.•Application studies were done in both artificial urine and blood serum.