A Fluorescent Probe Derived from L‐Tryptophan for Copper (II) Ion Detection in Aqueous Media

Abstract Copper (Cu 2+ ) is a transition metal ion extensively distributed in numerous foodstuffs of both animals and vegetables. An excess intake of Cu 2+ ions cause injury, pneumonitis, a disorder in the nervous system, and gastrointestinal problems. Hence, we have developed a simple and novel Schiff base‐based fluorescence sensor for the detection of Cu 2+ ions. The sensor, ‐3‐(1H‐indol‐3‐yl)‐2‐((4‐nitrobenzylidene) amino)propanoic acid (INAP), was synthesized from tryptophan and nitrobenzaldehyde by the reflux method and characterized by various analytical methods. The prepared INAP acted as a chemical sensor and displayed outstanding sensitivity and choosiness characteristics for Cu 2+ ions an aqueous solvent. In the presence of Cu 2+ , it demonstrated a fluorescence change in an aqueous medium with a “turn‐off” phenomenon via complex‐mediated energy transfer characteristics, and the method of continuous variation suggested a 1 : 2 complex formation of the metal ion with INAP. The LOD of the sensor system was calculated to be 1.3 μM for the Cu 2+ ion. In addition, the INAP fluorescent probe was applied to tap water samples and found acceptable recoveries. These results suggest that the newly fabricated sensor system would be explored as a chemosensor for the recognition of Cu 2+ ions in environmental samples.