eutech-instruments ammonium epoxy Manuel D’Utilisation

Ammonium Electrode 

 

Instruction Manual 

 

6

 
11.  Immerse the electrode tip(s) in the solution and wait for the reading to stabilize. Read the 

concentration directly from the meter display. 

 
12.  The electrodes should be re-calibrated every 1-2 hours. Simply repeat Steps 2-8 (2-9) 

above. 

 

 
This procedure is recommended for solutions with ionic strengths less than 1.0 x 10-

2

M. If the 

solution is high in ionic strength, but low in ammonium, use the same procedure, but prepare a 
calibration solution with a composition similar to the sample. 
 

1. 

Using 20 ml of stock ISA, dilute to 100 ml with distilled water. 

 
2. 

Dilute 1 ml of the 0.1M standard to 100 ml to prepare a 1.0x10-

3

M standard solution for 

measurements in moles per liter. Dilute 10 ml of the 1,000 ppm standard to 100 ml to 
prepare a 100 ppm  standard solution for measurements in ppm. 

 
3. 

To a 150 ml beaker, add 100 ml of distilled water and 1 ml of low level ISA. Place the 
beaker on the magnetic stirrer and begin stirring at a constant rate. 

 
4. 

Place the electrode tip(s) in the solution. Assure that the meter is in the mV mode. 

 
5. 

Add increments of the 1.0x10-

3

M or 100 ppm standard as given in Table 2 below. 

 
6. 

After the reading has stabilized, record the mV reading after each addition. 
 
     TABLE 2: Stepwise Calibration for Low Level Ammonium Measurements 
 
                                     

Added            Concentration      

  Step     

 Pipet            Volume (ml)      M          

  ppm    

 

1 

A 

0.1          

1.0X10-

6

 0.1 

 2 

A 

0.1 

2.0X10-

6

  

0.2 

 3 

A 

0.2 

4.0X10-

6

 0.4 

 4 

A 

0.2 

6.0X10-

6

 0.6 

 5 

A 

0.4 

9.9X10-

6

 1.0 

 6 

B 

 

2 

2.9X10-

5

 2.9 

 7 

B 

 

2 

4.8X10-

5

 4.8 

 

 

 

Pipet A = 1 ml graduated pipet 

 

Pipet B = 2 ml pipet 

 

7.  On semi-logarithmic graph paper, plot the mV reading (linear axis) against the 

concentration (log axis) as in Figure 1. 

 
8. 

Rinse the electrode(s) in distilled water and blot dry.