Molecular imprinting technology for electrochemical sensing of kasugamycin in food products based on Cu2+/Cu+ stripping current.

An electrochemical sensing approach was developed for the detection of the agricultural antibiotic drug kasugamycin. The method involves the construction of an electrochemical sensor comprising molecularly imprinted polymers (MIPs) embedded within a carbon paste (CP) matrix. The MIPs are designed to have imprinted sites that match the size and geometry of the Cu(II)-kasugamycin coordinated complex. Upon removal of kasugamycin, cavities suitable for the drug's entrance are formed within the MIPs. The presence of Cu(II) facilitates the detection of the drug by generating a redox signal of Cu(II)-Cu(I), which can be easily detected using differential pulse voltammetry (DPV). The signal response of Cu(II)-Cu(I) increases in the presence of the drug, promoting the accumulation of Cu(II) ions within the imprinted cavities. Under optimized conditions, the anodic peak (I_pa) signal of Cu(II)-Cu(I) exhibits an increase proportional to the concentration of kasugamycin within the range of 0.15-140 μM. The detection limit (LOD, S/N = 3) achieved is 0.046 μM. The proposed sensor demonstrates several characteristic features including good stability, reliable performance, a low detection limit, and excellent selectivity. The Cu(II)-MIP@CP sensor proved effective in detecting kasugamycin within complex samples like meat, milk, and cucumber, yielding recovery% ranging from 96.0 to 103.8%. Additionally, the relative standard deviation % (RSD%) fell within the range of 2.2% to 4.0%, indicating good precision and reliability.