A Colorimetric and Turn‐On Fluorometric Sensor for Real‐Time Naked‐Eye Detection of Al 3+ in Aqueous Solution and on Paper Strips
Maria Sadia, Robina Naz, Adil Zada, Muhammad ZahoorABSTRACT
Herein, a dual‐response sensor RN1, based on 3‐methoxybenzohydrazide and 2‐hydroxy‐1‐naphthaldehyde, was synthesized and characterized by FTIR, P‐XRD, 1 H‐NMR, and 13 C‐NMR. The sensor RN1 effectively showed colorimetric and turn‐on fluorometric response towards aluminum (Al 3+ ) with high sensitivity in a wide pH range (3–10). A 2:1 binding stoichiometry was confirmed between RN1 and Al 3+ by Job's plot analysis and theoretically using density functional theory (DFT) studies. The fluorescence enhancement of RN1 upon interaction with Al 3+ was attributed to the inhibition of C═N isomerization and the PET process of sensor RN1. The limit of detection was determined to be 6.7 × 10 −9 M. Sensor RN1 was highly specific to Al 3+ in the presence of potential interfering metal ions. Based on the reversible fluorescence response, an INHIBIT logic gate was constructed using Al 3+ and S 2− ions as two inputs. For on‐site detection of Al 3+ , RN1‐fabricated test strips were prepared. Sensor RN1 could fulfill various requirements in the environmental and biological fields.