Microwave-assisted synthesis of fluorescent carbon dots from nanocellulose for dual-metal ion-sensor probe: Fe (III) and Mn (II)

Abstract

A simple one-step microwave-assisted synthesis approach for preparing fluorescent carbon dots (CDs) with an average diameter of 7.86 nm from 2,2,6,6-tetramethylpiperidine-1-oxyl radical-mediated-oxidized cellulose nanofiber (TEMPO-CNF) and 4,7,10-Trioxa-1,13-tridecanediamine is reported in this study. The synthesized TEMPO-CDs exhibited excitation-dependent emission, with optimal excitation and emission wavelengths of 390 nm and 449 nm (bright blue ray), respectively. The fluorescence properties of the synthesized TEMPO-CDs were successfully and selectively quenched by Fe3+ within seconds and by Mn2+ after 10 min. Thus, this phenomenon is further applicable to the development of a fluorescence-sensing system for the quantitative detection of Fe3+ and Mn2+ using the same CD probe; this is the first time such findings have been reported in the CD-related literature.