eutech-instruments calcium epoxy Manuel D’Utilisation

Instruction Manual 

 

Calcium Electrode 

 

9

1. 

Dilute 10 ml  of the 0.1M standard to 1,000 ml to prepare a 1.0x10

-3

M standard solution 

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

 
2. 

Soak the calcium electrode for at least 1 hour in 1.0x10

-3

M or 100 ppm calcium standard 

solution. 

 
3. 

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

 
4. 

Place the electrode tips in the solution.  Assure that the meter is in the mV mode. 

 
5. 

Add increments of the 1.0X10

-3

M or 10 ppm standard as given in Table 2 below. 

 
6. 

After the reading has stabilized, record the mV reading after each addition. 

 

      

TABLE 2: Step-wise Calibration for Low Level Calcium Measurements 

 
                                      Added                  Concentration 
      

Step    Pipet    Volume (ml)           M               ppm 

       

1        A               0.1              1.0X10

-6

       1.0X10

-2

 

       

2        A               0.1              2.0X10

-6

       2.0X10

-2

 

       

3        A               0.2              4.0X10

-6

       4.0X10

-2

 

       

4        A               0.2              6.0X10

-6

       6.0X10

-2 

       

5        A               0.4              9.9X10

-6

       1.0X10

-1

 

       

6        B                2               2.9X10

-5

       2.9X10

-1 

       

7        B                2               4.8X10

-5

       4.8X10

-1 

 
      Pipet A = 1 ml graduated pipet 
      Pipet B = 2 ml  pipet 
      Solutions: additions of 1.0x10

-3

M or 10 ppm standard to 100 ml  of distilled water. 

 

7. 

On semi-logarithmic graph paper, plot mV reading (linear axis) against the concentration 
(log axis) as in Figure 1. 

 
8. 

Rinse the electrodes in distilled water and blot dry. 

 
9. 

Measure out 100 ml  of the sample into a 150 ml beaker and place the beaker on the 
magnetic stirrer and begin stirring. Lower the electrode tips into the solution. After the 
reading has stabilized, record the mV reading and determine the concentration from the 
low level calibration curve. 

 
10.  Prepare a new low level calibration curve daily. Check the calibration curve every 1-2 

hours by repeating Steps 2-7 above. 

 
Follow the procedure given for normal calcium determinations using an ion meter and the blank 
correction procedure.