A method of measuring the concentration of an analyte in sample presented to a sensor modified with an aptamer as bioreceptor, the sensor belonging to a sensor class, the method comprising the steps of: applying a pulsed voltammetric electrochemical method at a first frequency to obtain a first current value i 1; applying the electrochemical method at a second frequency to obtain a second current value i 2, wherein the first frequency and the second frequency generate a first and a second current response, respectively, when the electrochemical method is applied to any sensor of the sensor class that is modified with the aptamer, and said first and second current response are non-zero and not equal; calculating the concentration of the analyte by the equation T = Kd i 1 i 2 γ 2 − 1 γ 2 − γ 1 ∗ z + 1 − γ 1 γ 2 − γ 1 − 1 1 − γ 2 ∗ i 1 i 2 ∗ γ 2 − 1 zγ 2 − zγ 1 + 1 − γ 1 γ 2 − γ 1 wherein Kd is a dissociation constant for any sensor of the sensor class that is modified with the aptamer, γ 1 is equal to a ratio of a current response of target-saturated to target-free sample when the electrochemical method is applied at the first frequency for any sensor of the sensor class that is modified with the aptamer, γ 2 is equal to a ratio ot a current response ot target-saturated to target-free sample when the electrochemical method is applied at the second frequency for any sensor of the sensor class that is modified with the aptamer, and z is equal to a ratio of a current response of target-free sample when the electrochemical method is applied at the first frequency to a current response of target-free sample when the electrochemical method is applied at the second frequency for any sensor of the sensor class that is modified with the aptamer. applying a pulsed voltammetric electrochemical method at a first frequency to obtain a first current value i 1; applying the electrochemical method at a second frequency to obtain a second current value i 2, wherein the first frequency and the second frequency generate a first and a second current response, respectively, when the electrochemical method is applied to any sensor of the sensor class that is modified with the aptamer, and said first and second current response are non-zero and not equal; calculating the concentration of the analyte by the equation T = Kd i 1 i 2 γ 2 − 1 γ 2 − γ 1 ∗ z + 1 − γ 1 γ 2 − γ 1 − 1 1 − γ 2 ∗ i 1 i 2 ∗ γ 2 − 1 zγ 2 − zγ 1 + 1 − γ 1 γ 2 − γ 1 wherein Kd is a dissociation constant for any sensor of the sensor class that is modified with the aptamer, γ 1 is equal to a ratio of a current response of target-saturated to target-free sample when the electrochemical method is applied at the first frequency for any sensor of the sensor class that is modified with the aptamer, γ 2 is equal to a ratio ot a current response ot target-saturated to target-free sample when the electrochemical method is applied at the second frequency for any sensor of the sensor class that is modified with the aptamer, and z is equal to a ratio of a current response of target-free sample when the electrochemical method is applied at the first frequency to a current response of target-free sample when the electrochemical method is applied at the second frequency for any sensor of the sensor class that is modified with the aptamer.