Flower-like CoNi-LDH/PtNPs composites for highly efficient electrochemical sensing of methyl parathion in vegetables

CoNi-LDH/PtNPs synergistically enhances Hb immobilization and electron transfer. • Hb serves as the recognition element for simplified MP detection. • The sensor shows excellent selectivity, repeatability, and stability. • Good accuracy and precision for MP detection in real foods were achieved. In this study, a flower-like Co Ni bimetallic layered double hydroxide (CoNi-LDH) with a high specific area was synthesized, and CoNi-LDH/PtNPs composites were fabricated by self-assembling PtNPs onto the LDH surface. The resulting composites were employed to construct an electrochemical biosensing interface for the efficient detection of methyl parathion (MP). The porous CoNi-LDH, combined with the high conductivity of PtNPs, provided a suitable microenvironment for hemoglobin (Hb) immobilization, preserve bioactivity while accelerating electron transfer. This synergy significantly enhanced electrochemical response, improving detection sensitivity. The developed biosensor exhibited a linear response to MP in the range of 1–110 ng mL −1 with a detection limit of 0.38 ng mL −1 . In the analysis of vegetable samples, the sensor demonstrated reliable analytical performance, yielding recoveries of 91.1–102.1% with RSDs below 8.0% which were matched HPLC results ( R 2  = 0.9949). This work offers a practical electrochemical strategy for monitoring MP residues in agricultural products, demonstrating promising application prospect.