In this study, a novel competition-type electrochemiluminescent (ECL) immunosensor for detecting diclofenac (DCF) was fabricated with graphene oxide coupled graphite-like carbon nitride (GO-g-C₃N₄) as signal probe for the first time. The ECL intensity of carboxylated g-C₃N₄ was significantly enhanced after being combined with graphene oxide (GO) which exhibited excellent charge-transport property. The sensing platform was constructed by multiwalled carbon nanotubes and gold nanoparticles (MWCNTs-AuNPs), which not only provided an effective matrix for immobilizing a large amount of coating antigen but also facilitated the electronic transmission rate to enhance the ECL intensity. Based on the synergistic effect of GO-g-C₃N₄ and MWCNTs-AuNPs composite, the proposed sensor showed high sensitivity, good stability, and wide linearity for the detection of DCF in the range of 0.005–1000 ng mL⁻¹ with a detection limit of 1.7 pg mL⁻¹. Furthermore, the developed immunoassay has been applied to real samples with satisfactory results. Therefore, this work provided a promising method for the detection of DCF and other small molecular compounds in the future.

在这项研究中，首次以氧化石墨烯偶联的石墨状氮化碳（GO-gC ₃ N ₄）作为信号探针，制造了一种新型的竞争型电化学发光（ECL）免疫检测双氯芬酸（DCF）免疫传感器。羧基化的gC ₃ N ₄与氧化石墨烯（GO）结合后，其ECL强度显着提高，该氧化石墨烯具有出色的电荷传输性能。该传感平台由多壁碳纳米管和金纳米颗粒（MWCNTs-AuNPs）构成，不仅为固定大量包被抗原提供了有效的基质，而且还促进了电子传输速率以增强ECL强度。基于GO-gC ₃的协同作用N ₄和MWCNTs-AuNPs复合材料，在0.005–1000 ng mL ^-1范围内检测DCF的灵敏度高，稳定性好，线性范围广，检测限为1.7 pg mL ^-1。此外，已开发的免疫测定方法已应用于实际样品，结果令人满意。因此，这项工作为将来检测DCF和其他小分子化合物提供了一种有前途的方法。