Calibration of Volumetric flasks :
Weigh a clean & dry
volumetric flask. Calibrate the flask by filling it with recently boiled and
cooled distilled water at room temperature upto the mark and weigh the flask.
Determine the volume in ml by the formula;
Volume (in
ml) = (Weight in g / 0.99602)
Where 0.99602 g is the weight of 1
ml water determined at temperature 25°C.
For the volumetric flasks having
capacity more than 100 ml, dispense the water from 100 ml burette (class A) in
multiple steps if required and note the final volume (i.e. total volume
dispensed).
Calibration of one mark pipette / graduated pipette /
burette:
Calibrate the one mark pipette /
graduated pipette / burette by filling it with recently boiled and cooled
distilled water at room temperature upto the mark. Collect the water from
pipette into a clean, dry previously weighed beaker [For burette – drain the
water upto the lower mark]. Take the weight of beaker with water. Check the
weight of water by subtracting the wt. of empty beaker from weight of beaker
with water.
Determine the volume in ml by
the formula;
Volume (in
ml) = (Weight in g / 0.99602)
Where 0.99602 g is the weight of 1
ml water determined at temperature 25°C.
Tolerance limit
Volumetric flasks
Capacity
in ml
|
5
|
10
|
25
|
50
|
100
|
200
|
250
|
500
|
1000
|
|
Tolerance
(±ml)
|
Class A
|
0.02
|
0.02
|
0.03
|
0.04
|
0.06
|
0.08
|
0.1
|
0.15
|
0.2
|
Class B
|
0.04
|
0.04
|
0.06
|
0.08
|
0.15
|
0.2
|
0.2
|
0.3
|
0.8
|
|
One mark pipette
Capacity
in ml
|
1
|
2
|
5
|
10
|
15
|
20
|
25
|
50
|
100
|
|
Tolerance
(±ml)
|
Class A
|
0.006
|
0.006
|
0.01
|
0.02
|
0.02
|
0.03
|
0.03
|
0.04
|
0.06
|
Class B
|
0.02
|
0.02
|
0.03
|
0.04
|
0.04
|
0.05
|
0.06
|
0.08
|
0.12
|
|
Burettes
Capacity
in ml
|
10
|
25
|
50
|
100
|
|
Subdivision
in ml
|
0.05
|
0.05
|
0.1
|
0.1
|
|
Tolerance
(±ml)
|
Class A
|
0.01
|
0.03
|
0.05
|
0.1
|
Class B
|
0.02
|
0.06
|
0.1
|
0.2
|
|
Frequency : Initially when volumetric glassware is purchased.
Note : When the volumetric glassware do not comply with the
requirement as specified above, the volumetric glassware should be returned
back to party.
REFERENCE:
Indian Pharmacopoeia.
United States Pharmacopeia.
