Contamination of food 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 required. In this paper, a novel MnMgFe- LDHs/DC sensor is constructed based on a simple strategy, in which MnMgFe layered double hydroxide (LDHs) is used as a metal precursor, and a unique "island bridge" carbon network structure is generated by its pyrolysis with ZIF-8@B, N-WMCNTs. The electrical conductivity was enhanced, and a large electroactive surface area was provided for the MnMgFe- LDHs/DC. The electrochemical properties of Pb2+, Cd2+ and nitrite were investigated using this electrode as a working electrode. Under optimized conditions, the sensing platform exhibited a wide linear range with the Pb2+, Cd2+, and NO2 − limits of detection of 46.16 nM, 59.25 nM, and 0.083 μM, respectively. Of particular note is that this sensing platform exhibits outstanding anti-interference capabilities. It can precisely and efficiently conduct the detection of nitrite and heavy metal ions in pickled foods.

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.