OP90
Not Recommended for New Designs
Datasheet
OP90 on Analog.com
OP296
Production
The OP196 family of CBCMOS operational amplifiers features micropower operation and rail-to-rail input and output ranges.
The extremely low power requirements...
Datasheet
OP296 on Analog.com
Dear Team,
I will be using OP90 for implementing the circuit given below.The vendor suggests OP90.
The below circuit is obtained from here.

I did not completely understand this.My questions are given below.
May I know how this circuit maintains the Potential at Reference Electrode and Working Electrode same.
Here you can see that the working electrode is connected to IC1 and Refrence electrode to IC2.They are not in a common loop.Then how this circuit maintains same potential at working electrode and reference electrode.
Regards
HARI