Calibration of Glassware (Class A and Class B)

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 up to 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 up to the mark. Collect the water from the pipette into a clean, dry previously weighed beaker [For burette – drain the water up to the lower mark]. Take the weight of beaker with water. Check the weight of water by subtracting the wt. of empty beaker from the 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 does not comply with the requirement as specified above, the volumetric glassware should be returned back to the party.

REFERENCE

Indian Pharmacopoeia.

United States Pharmacopeia.

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