A method of determining an analyte concentration employs a biosensor that includes a molecularly imprinted polymer film formed on a metal layer. The biosensor is connected to a charge/discharge circuit and charged and discharged during exposure to a solution containing an analyte. Voltage values during discharge are measured, and a characteristic parameter of the voltage values, which is associated with a concentration of the analyte detected by the biosensor, is determined. An unknown concentration of the analyte is determined by comparing the characteristic parameter to reference data representing a relation between known concentration of the analyte and the characteristic parameter of the biosensor. A biosensor, such as an anesthetic biosensor, is also disclosed.