Electrochemical impedance spectroscopy detection of sodium ascorbate based on poly(T)-poly(AT-TA) dsDNA templated copper nanoclusters

Abstract

Sodium ascorbate (SA) is used as a source of vitamins for the human body, but the excessive intake can lead to symptoms such as diarrhea, stomach cramps or urinary calculi. In this work, the two DNA strands containing T-rich and AT-rich sequences were hybridized to form a double-stranded DNA (dsDNA), which was used as the template to in-situ synthesize copper nanoclusters (CuNCs). In the presence of SA, Cu²⁺ were reduced to Cu⁰ by disproportionation, and CuNCs were formed on the DNA template, resulting in the strong electrochemical impedance signal. Several important parameters such as the concentration of Cu²⁺ and the reaction time were optimized. Under the optimized conditions, the linear range was 5–300 μM, and the limit of detection was 0.98 μM for SA assay. In addition, a satisfactory recovery rate was obtained by using this method to detect SA in the beverage . Therefore, the developed detection method could detect SA sensitively and has a broad application prospect in food and biological analysis.