Week 18

A method to make Ag/AgCl electrodes using silver wire:

Construction of AgCl reference

 The body of the electrode is made from 4 mm glass tube. Vycor® porous glass is available in 4 mm diameter rod and serves as the ionic conducting electrical pathway


the inside of themreference electrode and the bulk of your cell.  It has low electrical resistance (under 10 kOhm for the common filling solutions) and a modest leak rate.

The electrical resistance of the reference electrode 'frit' is an important factor in determining the stability and speed of your potentiostat in actual use.  The leak rate may be important because of possible contamination of your solution by the reference electrode filling solution and vice versa.

The Vycor® frit (about 1/8" long) is attached to the glass tube by 'heat shrink' Teflon tubing.  The heat-shrink tubing should be cut flush with the end of the Vycor frit to prevent trapping any air bubbles. The cap is conveniently made out of scrap Teflon or plastic cap or protector made to fit 5/32" OD tubing. It should be snug, but easily removable for replenishing the filling solution.

Making a Silver Chloride

YouTube Video

Wire electrodes may yield better result than pellet electrodes.


- Look for silver wire and Cl- solution.
- Hand-made electrodes may not be as accurate as commercial electrodes.
- Interface and log data from oscilloscope.