Low-Cost and Efficient Neoliquiritin Monitoring via Sulfur and Phosphorus Co-Doped Graphene Oxide-Based Electrochemical Platform

In this study, a novel electrochemical sensor was developed for the highly sensitive and selective detection of neoliquiritin (NLQ), a bioactive flavonoid found in Glycyrrhiza uralensis. The sensor was constructed using sulfur and phosphorus co-doped graphene oxide (S, P-GO) as a nanomaterial-modified electrode, synthesized via a facile and eco-friendly hydrothermal method. The dual doping of sulfur and phosphorus not only enhanced the electrocatalytic activity of graphene oxide but also provided abundant coordination sites, facilitating efficient electron transfer and NLQ recognition. When deposited on a glassy carbon electrode (GCE), the S, P-GO/GCE sensor exhibited remarkable electrochemical performance for NLQ detection. Under optimized experimental conditions, the sensor demonstrated a wide linear detection range from ‌0.3 to 120 μM‌, with an exceptionally low detection limit of ‌0.075 μM (S/N = 3)‌. The sensor’s high sensitivity was attributed to the synergistic effects of S and P doping, which improved charge transfer kinetics and active surface area. Furthermore, the proposed sensor displayed excellent ‌selectivity‌ against common interferents, outstanding ‌stability‌ and ‌reproducibility‌. This work not only presents a robust and cost-effective platform for NLQ monitoring but also highlights the potential of heteroatom-doped graphene oxides in designing next-generation electrochemical sensors for phytochemical analysis.