Aucklandia lappa Decne carbon dots guided chemiluminescence: A sensitive detection strategy for salicylic acid

In this study, a novel chemiluminescent system was developed utilizing carbon dots (CDs) for the sensitive detection of salicylic acid. P,Cl co-doped carbon dots (P, Cl-CDs) was synthesized using discarded Aucklandia lappa Decne leaves as precursor materials through a one-step hydrothermal method. The morphology, structure, elemental composition, and properties of P, Cl-CDs were characterized by various methods including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The synthesized P, Cl-CDs exhibited uniform particle size and excellent water solubility. It was observed that P, Cl-CDs could significantly enhance the chemiluminescence intensity of the acidic KMnO4 system by approximately 10 times. While salicylic acid could inhibit the acidic KMnO4 system sensitized by P, Cl-CDs. Based on this phenomenon, a new system for detecting salicylic acid was established. Under optimal experimental conditions, the concentration of salicylic acid displayed a linear relationship in the range of 1 to 100 μM, achieving a limit of detection (LOD) of 4.2 nM and a relative standard deviation (RSD) of 0.9 % (n = 11). The method was successfully applied to determine salicylic acid in aspirin tablets, yielding spike recoveries within the range of 96.9 %–104.3 %.