Synthesis of nitrogen and sulfur codoped carbon dots and application for fluorescence detection of Cd(ii) in real water samples

Abstract

Herein, nitrogen and sulfur codoped carbon dots (N&S CDs) were prepared by a facile hydrothermal process and they could be introduced as a fluorescent probe for the determination of cadmium ions (Cd²⁺), yielding high sensitivity and excellent selectivity. The obtained N&S CDs exhibited bright blue fluorescence with a quantum yield of 40% and exhibited a fast responsive fluorescence quenching signal within 2 min toward Cd²⁺ in both ultrapure water and real water samples. The CDs responded to Cd²⁺, which acted as a quencher of blue fluorescence at 459 nm with the limit of detection of 0.018 μM in the range of 0.02–1 μM. The quenching fluorescence behavior was found to obey the static quenching effect (SQE). The low toxicity and good cell permeability of CDs were verified by cell experiments.