A green path to extract carbon quantum dots by coconut water: Another fluorescent probe towards Fe3+ ions--颗粒学报PARTICUOLOGY

Preethi, M., Viswanathan, C., & Ponpandian, N. (2021). A green path to extract carbon quantum dots by coconut water: Another fluorescent probe towards Fe3+ ions. Particuology, 58, 251-258. https://doi.org/10.1016/j.partic.2021.03.019

A green path to extract carbon quantum dots by coconut water: Another fluorescent probe towards Fe³⁺ ions

Manoharan Preethi, Chinnuswamy Viswanathan, Nagamony Ponpandian ^*

Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046, India

10.1016/j.partic.2021.03.019

Volume 58, October 2021, Pages 251-258

Received 4 January 2021, Revised 13 March 2021, Accepted 31 March 2021, Available online 28 April 2021, Version of Record 13 September 2021.

E-mail: ponpandian@buc.edu.in

Highlights

• Fluorescent CQDs are prepared using coconut water by stirrer-assisted technique.

• Low cost, non-toxic, rapid, and environmentally friendly with neutral pH of 70 °C.

• The CQDs showed blue fluorescence at an excitation wavelength of 390 nm.

• The fluorescence sensor for Fe³⁺ detection of 0–700 μM with the LOD of 0.30 μM.

Abstract

In recent years, carbon quantum dots (CQDs) have been of great enthrallment in the fluorescent probe field. Carbon precursors with interesting physicochemical properties may be derived from natural sources. In this research, for the first time, coconut water has been used as a source of carbon to prepare blue fluorescent CQDs without any modification and functionalization. The preparation of CQDs is very simple and cost-effective, when compared with other conventional techniques. The reaction parameters temperature and pH were varied to obtain monodispersed spherical CQDs with an average grain size of ∼5 nm. The CQDs exhibit blue emission with a wavelength of 487 nm with an excitation wavelength of 390 nm and are used for Fe³⁺ ions detection. Fe³⁺ ions have been observed to quench the fluorescence intensity of the CQDs than other heavy metals. In the presence of Fe³⁺ ions, the fluorescent CQDs are quenched due to the interaction of CQDs and Fe³⁺ ions. A spectroscopic result shows that Fe³⁺ ions can be observed within a concentration of 0–700 μM, as well as the detection limit is 0.30 μM. The CQDs provide a unique pathway for potential application in the environmental monitoring of heavy metal ions.

Graphical abstract

Keywords

Green preparation of CQDs; Coconut water; Stirrer-assisted technique; Detection of metal ions; Quenching efficiency; Nonfluorescence

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