ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

“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

E-mail: swambabu@che.iitkgp.ac.in

Received: 13 September 2023  Accepted: 30 November 2023

Abstract:

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 www.springerlink.com.

DOI: 10.1007/s11696-023-03255-8

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