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Calibration of Volumetric Glassware used in Pharmaceuticals


Calibration of laboratory glass ware class A and class B, pipette / graduated pipette / burette and volumetric flasks. Tolerance limit and Frequency of Calibration.

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.

Also see: Cleaning of Glassware with Nitric Acid and Chromic Acid

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of Pharmaceutical Guidelines, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
Email: .moc.enilediugamrahp@ofni Need Help: Ask Question


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