Fluorescent-colorimetric dual-mode sensor based on Schiff base for selective detection of picric acid
A pyrazinyl salicylaldehyde imine Schiff base fluorescent chemical sensor has been successfully synthesized using 2-pyrazine hydrazine and 4-(diethylamino)salicylaldehyde as substrates for the selective detection of picric acid(PA).Upon contact with PA,the sensor undergoes fluorescence quenching,which is attributed to the intermolecular charge transfer effect between the sensor and PA,as confirmed by Job's plot analysis and nuclear magnetic resonance hydrogen spectroscopy experiments.In solution,the sensor exhibits good selectivity for PA with a detection limit as low as 5.18 ×10-7 mol/L and a linear range of 0-40 μmol/L,making it suitable for quantitative analysis.Additionally,the sensor can be adsorbed onto cotton swabs and silica gel plates,enabling in-situ detection of PA through a colorimetric method.