“Turn ON-OFF-ON” photoluminescence detection of EDTA using Moringa oleifera gum-derived carbon dots

Abstract

This study offers a simplistic approach to hydrothermally synthesizing photoluminescent carbon dots (CDs) using Moringa oleifera Gum (MOG) to detect and quantify EDTA. The as-synthesized Moringa oleifera Gum-derived CDs (MOG-CDs) exhibited an average size of 3.41±0.44 nm and are amorphous. They are naturally doped with calcium and sulphur. Functional groups linked with these heteroatoms and oxygenated linkers are responsible for excellent water dispersibility, good stability, and remarkable optical properties of MOG-CDs. The MOG-CDs demonstrated a high quantum yield of 27.53%. The PL intensity of MOG-CDs was selectively quenched by the introduction of Pb2+ ions, which were further used as a passivating agent for EDTA detection, i.e., the quenched PL can be restored by the addition of EDTA into MOG-CD+Pb2+ system. This Turn “ON-OFF-ON” strategy was used to quantify EDTA with a LOD of 2.6 ppb (8.9 nM). The practicality and viability of the proposed photoluminescent probe were validated by quantifying EDTA in actual samples. The results demonstrated favourable spiked recoveries ranging from 92.59% to 108.69%, indicating a high level of accuracy. Additionally, it displayed excellent reproducibility, as suggested by relative standard deviation (RSD) <5.51%. In parallel, an "IMPLICATION" Boolean logic gate was constructed by employing the PL restoration of the MOG-CD+Pb2+ sensing probe in the presence of EDTA.