Salicyaldehyde-based fluorescent sensors with high sensitivity for amino acids

Structurally simple salicylaldehyde-based fluorescent sensors for amino acids have been obtained by one-step or two-step synthesis. These sensors show significant fluorescence enhancement in the presence of many amino acids at concentrations as low as 10−5 mol/L. The reversible reaction of the aldehydes with amino acids to form imines in aqueous solution is proposed to account for the observed fluorescence enhancement.