Dual-signal N-CDs/COFTAPB-DMTP sensor for simultaneous detection and adsorption of aflatoxin B1 in peanuts

Aflatoxin B 1 (AFB 1 ), the most potent natural carcinogen, poses a serious threat to food security and human health. Hence, monitoring and controlling AFB 1 levels in food is of paramount importance. Nitrogen-doped carbon dots (N-CDs) exhibit great potential for sensing applications, but their single-intensity signals are often susceptible to interference. Covalent organic frameworks (COFs) have been widely applied in sensing and adsorption. By integrating N-CDs with COFs, a hybrid material named N-CDs/COF TAPB-DMTP was constructed as a ratiometric fluorescent probe for AFB 1 detection. The sensing platform not only retains the exceptional optical properties of N-CDs but also incorporates the superior adsorption capabilities of COFs. Here, N-CDs/COF TAPB-DMTP showed outstanding sensitivity with a remarkably low detection limit of 0.0876 ng/mL and a linear range from 0.5 to 100 ng/mL. The developed sensor also exhibited excellent reproducibility, anti-interference capability, and stability. In spiked food samples, satisfactory recovery rates of 90.00% to 126.00% were achieved. Furthermore, the probe accurately distinguished between AFB 1 -positive and negative peanuts, matching results from colloidal gold test cards and ELISA. Owing to its high surface area and selective sites, this composite showed an outstanding AFB 1 adsorption capability of 91.7431 mg/g. Density functional theory (DFT) calculations were employed to elucidate the adsorption mechanism between COF TAPB-DMTP and AFB 1 , which was shown to involve weak hydrogen bonds and π-π stacking interactions. Overall, a new dual-function platform has been constructed for the highly sensitive monitoring and efficient elimination of AFB 1 , offering a low-cost and simple-operating strategy with significant potential for food safety control.