LAUSR

Abstract A new dual mode chemosensor 8-methoxy-2-(thiophen-2-yl) quinolone (L) was synthesised for selective and sensitive detection of Bi3+ ions. The selective distinct colorimetric response and fluorescence quenching were observed upon interaction of L with Bi3+ in CH3CN:H2O (85:15, v/v) media. The sensor L could form 2:1 stoichiometric complex with Bi3+ with an association constant of 2.2 × 105 M−2 by using Benesi-Hilderbrand (BH) method. The fluorescence quenching constant estimated to be 9.3 × 108 M−1 by using Stern-Volmer (SV) plot. The lowest detection limit of Bi3+ by colorimetric and fluorimetric were found to be 1.78 μM and 0.057 μM respectively. The sensing mechanism of L with Bi3+ was studied using 1H NMR, ESI-mass analysis and theoretical calculations. Finally, the sensor L was applied for the detection of Bi3+ in various water and pharmaceutical drug samples.