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

Surface-functionalized fluorescent carbon dots (CDs) for dual-mode detection of lead ions

Amy Bamrah, Harpreet Singh, Shalini Singh, Sanjeev Kumar Bhardwaj, Madhu Khatri, Akash Deep, and Neha Bhardwaj

Department of Biotechnology, University Institute of Engineering & Technology (UIET), Panjab University, Chandigarh, India

E-mail: nehavashisht1989@gmail.com

Received: 26 March 2022  Accepted: 30 May 2022

Abstract:

In the present study, the highly fluorescent CDs, functionalized with 3-mercaptopropionic acid (3-MPA), were synthesized via a green chemistry route and subsequently employed as a dual-mode (fluorescence and turbidimetric) optical sensor probe (MPA@CDs) for Pb²⁺ ions. The as-synthesized CDs (average size of 8 nm) exhibited bright-blue fluorescence with a quantum yield of around 16%. The addition of lead (Pb²⁺) ions to the MPA@CDs solutions caused an enhancement in their fluorescence due to the strong interaction between MPA and Pb²⁺_. This strategy has provided a “turn-on” type of sensing of Pb²⁺ with a limit of detection (LOD) of 51 pM. Further, the reaction of MPA@CDs with Pb²⁺ was characterized by a significant change in the solution turbidity. This visible detection method could analyze Pb²⁺ with a LOD of 13.2 nM. Both the above strategies developed with the aid of MPA@CDs demonstrated high sensitivity and selectivity with the rapid response toward Pb²⁺ ions even in the spiked real water samples. Therefore, the prepared nanosensor can provide a promising platform for the analysis of Pb²⁺ ions in aqueous environmental and biological samples.

Graphical abstract

Keywords: Carbon quantum dots; Fluorescence; Heavy metals; MPA@CDs; Pb2+

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02307-9

Chemical Papers 76 (10) 6193–6203 (2022)