Patent ID: 7164162

Claim:
A manufacturing method of a potassium/sodium ion sensing device applying an extended-gate field effect transistor, the method comprising the steps of: Step 1: depositing a SnO 2 thin film on an ITO glass substrate as a solid-state sensing substrate; Step 2: adhering a silver paste to said ITO glass substrate and a conducting wire; Step 3: using epoxy resin to seal said silver paste and said conducting wire, and to package a sensing window; Step 4: forming a polymer ion selective membrane including a photo-curable polymer, a photo-initiator, a electronegative additive, a potassium ionophore or sodium ionophore by the steps of: Step (a): intermixing a hydro-aliphatic urethane diacrylate (EB2001) with a photo-initiator; Step (b): adding a photo-curable polymer into the mixture of step (a) and intermixing in an ultrasonic bath; Step (c): adding a potassium ionophore or sodium ionophore, an electronegative additive into the mixture of step (b); Step (d): intermixing the mixture of step (c) in an ultrasonic bath; Step 5: immobilizing said polymer ion selective membrane in said sensing window.