Electrochemical determination of chlorogenic acid using an AuNPs/C-MWCNTs-ErGO nanocomposite sensor

Rapid and accurate quantification of chlorogenic acid (CGA) is critical for the quality control of herbal pharmaceuticals. Herein, a sensitive electrochemical sensor was constructed through an electrochemical strategy whereby graphene oxide (GO) doped with carboxylated carbon nanotubes (C-MWCNTs) was reduced via cyclic voltammetry and gold nanoparticles (AuNPs) were subsequently potentiostatically deposited onto a C-MWCNTs-ErGO film, forming a ternary AuNPs/C-MWCNTs-ErGO nanocomposite on a glassy carbon electrode. The conductive C-MWCNTs-ErGO framework together with the electrocatalytic AuNPs synergistically accelerated electron transfer for CGA oxidation. The sensor delivered broad linear response ranges of 0.05-20 μM and 20-200 μM and a detection limit as low as 0.017 μM. It also exhibited favorable anti-interference capability, satisfactory repeatability and reproducibility, and maintained over 92% of its initial signal after 21 days of storage. Practical application to Honeysuckle and Eucommia ulmoides oral liquids yielded recoveries of 93.0%-97.1% with relative standard deviations below 6%, demonstrating the sensor’s promise for pharmaceutical quality assessment.