A novel, ultra-high sensitivity electrochemical aptamer biosensor (EAB) was fabricated by immobilising gold nanoparticles (Au) on a nano-confined interface of N-doped carbon nanofibers/carbon fibers (N-CNFs/CFs). Gold nanoparticle-thiol (Au–S) conjugates, coupled with aptamer-specific recognition technology, were used to immobilise aflatoxin B1 (AFB1). The nanoconfined interface of N-CNFs/CFs provides more binding sites for Au with its unique spatial structure and electroactive surface area, enhancing the electrochemical performance of the matrix. Compared to the existing sensor detection limit, the limit of detection(LOD) of the EAB was approximately 6.4 pg/mL. The dynamic detection ranged from 10.0 to 1.0 × 108 pg/ mL. Furthermore, AFB1 was also successfully detected in Chinese Materia Medica decoction pieces(CMMDP) using the prepared EAB, with recoveries ranging from 96.18 to 112.87%. These results demonstrate the proposed EAB’s potential as a reliable tool for rapid and efficient detection of AFB1 in complex matrices.

Food contamination with heavy-metal ions and nitrites poses a serious threat to human health. Consequently, the development of fast and sensitive platforms for detecting these contaminants is urgently needed. In this study, a novel sensing platform was developed by integrating carbon nanotubes generated by the pyrolysis of waste masks (WMCNTs) with ZIF-8 for the simultaneous detection of Cd2+, Pb2+, and nitrite. Specifically, the electronic structure of the WMCNT backbone was modulated by doping with B and N atoms. Nanoporous ZIF-8 was then grown in-situ on its surface to produce composites with enhanced electrical conductivities and large specific surface areas. This modification provided more active sites for the attachment of heavy-metal ions and nitrites. Under optimized conditions, the sensing platform exhibited a wide linear range with the Pb2+, Cd2+, and NO2 − limits of detection of 2.68, 12.12, and 5.94 μM, respectively. Notably, the sensing platform demonstrated excellent anti-interference capabilities and effectively detected nitrites and heavy-metal ions in pickled foods.

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature (600–850°C) on the CO2 adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of 1488 m2 g–1 was achieved at an activation temperature of 800°C (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to 850°C. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, CO2 adsorption isotherms showed that AC-800 exhibited the best CO2 adsorption capacity of 110 mg g–1 at 298 K and 1 bar.