eutech-instruments ammonia gas ユーザーズマニュアル

Instruction Manual 

 

Ammonia Gas-sensing Electrode

 

 

3

the electrode body up at the threads with thumb and forefinger. Place one edge of the 
membrane against the threads and hold in place with your thumb. Stretch new membrane 
lengthwise across the electrode opening so that it smoothly covers the opening. Place the 
other edge of the membrane against the threads and hold in place with your forefinger. 

 
4. 

Place the bottom cap gently over the membrane onto the threads and screw the bottom cap 
on until finger-tight. Check that the membrane is free of wrinkles and holes or else repeat 
the above steps. 

 
5. 

Using the syringe provided, fill the outer body with approximately 2 ml of inner filling 
solution. Place glass inner body into epoxy outer body containing the internal filling 
solution and screw on the upper cap until finger-tight.  

 

 
Connect the electrode to the meter according to meter manufacturer's instructions. No external 
reference electrode is required. To prevent air entrapment, mount the electrode at a 20

o

 angle from 

the vertical. 
 

(check electrodes each day) 
 

1. 

To a clean, dry, 150 ml beaker, add 100 ml of distilled water and 1 ml of ISA. Place the 
beaker on a magnetic stirrer and begin stirring at a constant rate. After assuring that the 
meter is in the millivolt mode, lower the electrode tip into the solution. Remove air bubbles 
by redipping probe. 

 
2. 

Using a pipet, add 1 ml of 0.1M or 1,000 ppm standard into the solution. When the reading 
has stabilized,  record the mV value. 

 
3. 

Using a pipet, add 10 ml of the same ammonia standard used above to the beaker. When 
the reading has stabilized, record the mV value.   

 
4. 

Determine the difference between the two readings. The electrode is operating correctly if 
a difference of 56±3 mV is found, assuming the solution temperature is between 20

o

 and 

25

o

C. See the 

 section if the potential change is not within this range. 

 

Slope is defined as the change in potential observed when the concentration changes by a factor of 
10. 
 

(check electrodes each day) 
 

1. 

Prepare standard ammonia solutions whose concentrations vary by tenfold. Use either the 
0.1M or 1,000 ppm ammonia standard. Use the serial dilution method for this preparation. 

 

2. 

To a 150 ml beaker, add 100 ml of the lower value standard and 1 ml of ISA. Place the 
beaker on the magnetic stirrer and begin stirring at a constant rate. Lower the electrode tips 
into the solution.  Assure that the meter is in the concentration mode.