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

In this study, a flower-like CoNi 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 (R² = 0.9949). This work offers a practical electrochemical strategy for monitoring MP residues in agricultural products, demonstrating promising application prospect.