STANDARDIZATION OF A 1.0 ml VOLUMETRIC PIPETTE
- Importance
- Principle
- Requirement
- Procedure
Importance:-
1.0 ml volumetric pipette is used for pipetting solutions. For accurate transfer of a solution, the volumetric pipette of 1.0 ml must deliver exactly 1.0 ml of the specimen.
Principle:-
The volume of water dispensed by 1.0 ml volumetric pipette is weighed by using an analytical balance. The Table 2.2 indicates the weight of 1.0 ml of water at different temperatures. Average weight is calculated. Percent deviation error should not be greater than + 5%.
Requirement:-
1. Volumetric pipette of 1.0 ml
2. A 10 ml beaker
3. Distilled water (sample)
4. Weights
5. Analytical balance
Procedure:-
1. Weight of empty beaker =X g
2. Weight of beaker + 1.0 ml of distilled water = Y g
3. YX weight of 1.0 ml of distilled water,
4. Repeat steps 1 to 3 at least twice.
5. Calculate ‘D’ by using following table (Table 2.2). D= Average difference between the expected weight weight of 1.0 ml of distilled water.
6. Calculate % deviation error by using the following formula:
% deviation error = D/Wc x 100
Additional information:-
The accuracy of various volumetric and push button pipettes can be determined by this simple experiment.
Example: Standardization of 0.05ml pipette.
Procedure:-
Same as above. To make 1.0 ml of distilled water, dispense 0.05 ml distilled water 20 times in the beaker.
NOTE:-
Mercury can be used instead of distilled water. The density of mercury at room temperature = 13.56 g/cm³
