Patent ID: 8858780

Claim:
A method for determining a concentration of an anesthetic in a solution, comprising: (a) providing a biosensor that includes two sensor electrodes each of which has a metal layer and a molecularly imprinted polymer film formed on the metal layer, said molecularly imprinted polymer film being imprinted by a template molecule to form a plurality of molecular recognition cavities for capturing molecules of the anesthetic; (b) exposing the biosensor to the solution; (c) connecting a charge/discharge circuit to the biosensor that has been exposed to the solution, the charge/discharge circuit including a discharge capacitor coupled between the sensor electrodes; (d) applying a constant voltage to the charge/discharge circuit to charge the charge/discharge circuit and the biosensor; (e) discharging the charge/discharge circuit and the biosensor after the charge/discharge circuit and the biosensor are saturatedly charged; (f) measuring varying voltages across the discharge capacitor during discharge to obtain a set of varying voltage values that vary with time; (g) determining a characteristic parameter of the voltage values associated with the concentration of the anesthetic detected by the biosensor; and (h) determining the concentration of the anesthetic by comparing the characteristic parameter with reference data representing a relation between an anesthetic concentration and characteristic parameters of the biosensor.