A new SPR sensor for the detection of nicosulfuron herbicide was prepared based on a combination of molecularly imprinted technique with surface plasmon resonance (SPR) spectroscopy. In the process of this experiment, the effect of pH value on the adsorption of the imprinted membrane to the analyte was investigated. Meanwhile, we also evaluated the properties of its adsorptivity and selectivity at the optimal pH. Compared to the non-imprinted polymer, the imprinted polymer showed higher adsorption efficiency for nicosulfuron than that of other structurally related analogues. The method showed good linearity between 5.0×10^－12～25×10^－12 mol/L. The association constant of the imprinted sites in the composite to nicosulfuron (K_ass) was calculated to be 1.6×10¹⁰ L/mol and the change in Gibb s free energy was －58.148 kJ/mol. The results indicated that the developed SPR sensor for the detection of nicosulfuron possessed the advantages such as simplicity, high-speed, high sensitivity and good recovery and when it was used to determine the nicosulfuron herbicide in the tap water and soil, based on a signal to noise ratio of 3, the detection limits were 5.62×10^－14 mol/L and 1.01×10^－13 mol/L, the mean recoveries were 85.6% and 76.6%, the relative standard deviations (RSD) obtained were 1.78% and 3.21% for the tap water and soil, respectively.

Key words: molecularly imprinted technique, surface plasmon resonance sensor, nicosulfuron