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“Turn ON–OFF” detection of lead using Moringa oleifera gum-derived cyan-emissive carbon dots integrated with a smartphone-assisted sensing platform

Anisha Mandal, Ankita Karmakar, and Swambabu Varanasi

Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, India



Received: 13 September 2023  Accepted: 30 November 2023


Lead poisoning is one of the most common and preventable environmental health problems. Prevention is directly correlated with detection and quantification. This report provides a green, facile and economical approach to synthesizing carbon dots (CDs) from Moringa oleifera gum (MOG) which can quantify the lead in environmentally desecrated samples like water, e-waste leachate using a smart phone for the first time. The synthesized MOG-CDs are functional group-rich and are naturally doped with calcium and sulfur, which enhances their photoluminescence. The intrinsic nature of MOG-CDs displayed a photoluminescence “Turn ON–OFF” mechanism even in trace amounts of Pb2+ ions. MOG-CDs selectively and sensitively detect Pb2+, with a detection limit (LOD) of 0.41 ppb (1.08 nM). The photoluminescent probe quantified Pb2+ in actual water and electronic waste samples. The relative standard deviation (RSD) of < 7% makes its performance highly reproducible. The probe has high sensitivity, selectivity, repeatability, stability, and applicability. Furthermore, the Pb2+-induced photoluminescence quenching recognition using a smartphone-based portable sensing platform showed excellent linearity (R2 = 0.9961) within the range of 0–100 ppb, with satisfactory sensitivity (LOD = 4.41 ppb (11.62 nM)). The demonstrated photoluminescent sensing probe offers palatable results, extending its potential applications in resource-constrained areas.

Keywords: Carbon dots; Moringa oleifera gum; Photoluminescent sensor; Heavy metal detection; E-waste; Smartphone-based device

Full paper is available at

DOI: 10.1007/s11696-023-03255-8


Chemical Papers 78 (4) 2493–2507 (2024)

Tuesday, May 21, 2024

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