A simple electrochemiluminesecence aptasenor using a GCE/NCQDs/aptamers for detection of Pb

An electrochemiluminescence (ECL) aptasensor was prepared to detect Pb²⁺ with nitrogen-doped carbon quantum dots (NCQDs) as ECL materials. To prepare the working electrode, NCQDs with carboxyl groups were loaded on a glassy carbon electrode (GCE) and then Pb²⁺ aptamers were covalently bound to the NCQDs to form a stable GCE/NCQDs/aptamers. On addition of Pb²⁺, the chain aptamers change to a pb²⁺ G-quadruplex conformation, which lead to a large decrease in the ECL intensity. The variation of intensity and the logarithm of the Pb²⁺ concentration had a good linear relationship (R² = 0.998). The detection range was wide (50 pM to 387.9 nM) with a low detection limit (18.9 pM). In interference experiments, the ECL Pb²⁺ aptasensor did not suffer from interference and it had good stability. The NCQDs ECL aptasensor can detect Pb²⁺ quickly and accurately, and provides a fast and efficient method for detection of Pb²⁺. Compared with literatures, the Pb²⁺ aptasensor has simpler preparation process, lower cost; furthermore, it is more environmentally friendly.