Surface-enhanced infrared attenuated total reflection spectroscopy via carbon nanodots for small molecules in aqueous solution

In this study, carbon nanodots (CNDs) with excellent aqueous dispersibility, narrow size distribution, and oxygen-rich functional groups have been prepared via a green electrochemical method. Graphite electrodes were directly electrolyzed at ambient temperatures to form uniform CNDs in deionized water, which is free from additional oxidant/reductant. As-synthesized CNDs have been applied to coat an attenuated total reflection (ATR) waveguide enabling surface-enhanced infrared absorption (SEIRA) spectroscopic studies for detecting a variety of analytes in aqueous phase with remarkably enhanced IR band intensities. Finally, the proposed ATR-SEIRA strategy enabled quantitatively analyzing adenine in aqueous solution after optimizing the amount of CNDs, the solution pH, and potential CND aggregation.