Chromolaena Odorata Leaves Derived Carbon Dot‐Based Fluorescence/Second‐Order Scattering Ratiometric Sensor for Fe3+ and Vitamin C

Abstract

Herein, a ratiometric fluorescence and second‐order scattering sensor with plant leaf‐derived carbon dots (CDs) for Fe3+ and vitamin C is reported. The CDs are prepared from Chromolaena odorata leaves through a one‐pot hydrothermal method. The synthesized CDs have a quantum yield of 22.6%. The spherical dots have an average size of 3 nm and the chemical composition is found as nitrogen (7%) being the highest heteroatom present along with carbon and oxygen atoms in it. The ratio between fluorescence intensity at 445 nm and second‐order scattering constitutes the sensor output. A linear relationship is found between the output and analyte concentration in the range 0–70 and 0–10 μM with limit of detection 0.12 and 1.2 μM for Fe3+ and vitamin C, respectively. Static mechanism along with inner filter effect has been identified as the underlying quenching mechanism for Fe3+ activity. The strong chelation of Fe3+ by vitamin C further enhances the fluorescence. The change in the second‐order scattering intensity is explained by the formation and disruption of CDs/Fe3+ complex. The sensor also shows satisfactory performance with borewell water (Fe3+) and commercial tablet (vitamin C) with recovery rate ranging between 98.6% and 103.5%.