pH Adaptor & Electrode
15
Connect the pH sensor to the computer, open the EasySense2 software and check the range of
the pH sensor is set to ±1000 mV.
In Setup check the mode is Continuous, select a
Numeric chart and Start logging.
Rinse the electrode with distilled water. Dab or
pat gently any excess water from the body of the
electrode using a paper towel.
Place the pH electrode in the beaker of the first
buffer solution, allow the reading to stabilise and
write down the mV reading and the pH value of the
buffer in a results table.
Rinse the electrode with distilled water. Dab or pat gently any excess water from the body of the
electrode using a paper towel.
Place the pH electrode in the beaker of the second buffer solution, allow the reading to stabilise
and write down the mV reading and the pH value of the buffer.
Repeat for all buffers supplied.
Draw a graph with the pH buffer value on the X axis (from 0 to 14) vs. mV reading on the Y axis.
Draw a best fit line.
This graph can be used to find the pH value for the mV reading from the sensor.
For example we used 9 different buffers:
pH of buffers
2
2.93
4.01
4.95
6.0
6.99
7.97
8.97
9.95
mV reading
287
222
163
105
47
-10
-67
-123
-175
-500
-400
-300
-200
-100
0
100
200
300
400
500
0
2
4
6
8
10
12
14
m
V
pH
e.g. a 300 mV reading = a pH of 12
e.g. a 200 mV reading = a pH of 3.3
