The Integration of Reference Electrode for ISFET Ion Sensors Using Fluorothiophenol-Treated rGO.

Ion-sensitive field-effect transistors (ISFETs) detect specific ions in solutions that enable straightforward, fast, and inexpensive sensors compared to other benchtop equipment. However, a conventional reference electrode (RE) such as Ag/AgCl is limited on the miniaturization of the sensor. We introduce reduced graphene oxide (rGO), which serves as a new RE, when fluorinated (F-rGO) using fluorothiophenol through the π-π interaction.

Two-Dimensional Disposable Graphene Sensor to Detect Na Ions.

The monitoring of Na ions distributed in the body has been indirectly calculated by the detection of Na ions in urine. We fabricated a two-dimensional (2D) Na ion sensor using a graphene ion-sensitive field-effect transistor (G-ISFET) and used fluorinated graphene as a reference electrode (FG-RE). We integrated G-ISFET and FG on a printed circuit board (PCB) designed in the form of a secure digital (SD) card to fabricate a disposable Na ion sensor.