Patent ID: 8366905

Claim:
A method of detecting ionic materials, the method comprising: detecting a sensing voltage according to a concentration of ionic materials in a liquid sample using a sensing electrode of an apparatus, the apparatus comprising a first switching transistor having a first terminal connected to the sensing electrode and a second terminal connected to a first node; a second switching transistor having a first terminal connected to a reset voltage and a second terminal connected to the first node; and a sensing transistor having a gate connected to the first node; and the sensing electrode contacting the liquid sample; applying the sensing voltage to the gate of the sensing transistor; measuring a first gate voltage corresponding to the sensing voltage being applied to the gate of the sensing transistor; applying a reset voltage to the gate of the sensing transistor; measuring a second gate voltage corresponding to the reset voltage being applied to the gate of the sensing transistor; and calculating a voltage difference between the first gate voltage and the second gate voltage.