SOP for Calibration of Glassware | How to Calibrate Analytical Glassware | QC Glassware |

 

OBJECTIVE

To lay down the Standard Operating Procedure for Calibration and Cleaning of Glassware.

SCOPE

This procedure is applied for Standard Operating Procedure for Calibration and Cleaning of Glassware.

RESPONSIBILTY

QC Executives

QC Manager 

PROCEDURE FOR CALIBRATION OF GLASSWARES

Only Class A grade glassware are used for quantitative analysis. This procedure is applicable for class-B grade glassware which are to be used for quantitative analyses

Volumetric flasks

Clean and dry the volumetric flasks to be calibrated and condition the flask to the temperature at which the calibration is being carried out. Mark the glassware with a serial number (with sticker). Place the volumetric flask to be calibrated, on the balance pan. Weigh and record the empty weight of volumetric flask. Measure and record the temperature of water to be used for calibration. Fill the volumetric flask to the mark with water. Wipe the outside of the flask to dryness and weigh. Record the weight of the flask with water. Record the density of water corresponding to the temperature recorded. Apply correction factor on volume for temperature and pressure from the tables of Indian standard IS 8897:1978. Calculate the volume (in ml) as per the following equation,

V flask = W (flask + water) – W(flask) / Density of water

Repeat the processes 4.2.3 to 4.2.9 for 6 times. Calculate and record the average flask volume, error and uncertainty in the prescribed format. Ensure that the flask error is within the acceptable criteria (tolerance).. Record the observations as per Format 1

 

Pipettes and burettes

Take the weight of a clean, dry beaker & note the weight of it. Fill the glassware being calibrated with distilled water to the mark and transfer the water from the glassware to beaker & weigh. Record the density of water corresponding to the temperature recorded. Apply correction factor on volume for temperature that is the cubical thermal expansion of glass. The volume of measuring glassware under calibration is calculated by the following equation.

V glassware= W (beaker + water) – W(beaker) / Density of water

Repeat the processes 4.3.1 to 4.3.5 for 6 times. Calculate and record the average flask volume, error and uncertainty in the prescribed format. Ensure that the flask error is within the acceptable criteria (tolerance). Record the observations as per Format 1

Acceptance Criteria:

Volumetric flask: 

Capacity in ml	5	10	25	50	100	200	250	500	1000
Tolerance (± ml)	0.04	0.04	0.06	0.08	0.15	0.20	0.20	0.30	0.80

Pipettes: 

Capacity in ml	1	2	5	10	15	20	25	50	100
Tolerance (± ml)	0.02	0.02	0.03	0.04	0.04	0.06	0.06	0.08	0.12

Burettes: 

Capacity in ml	10	25	50	100
Tolerance (± ml)	0.02	0.06	0.10	0.20

Measuring cylinders: 

Capacity in ml	5	10	25	50	100	250	500	1000
Tolerance (± ml)	0.1	0.2	0.5	1.0	1.0	2.0	5.0	10.0

 

Precautions:

The balance used should be calibrated. Before starting calibrations, the glassware should be clean and is free from dust, grease or oil. Dry the glassware at room temperature. Before weighing the flask, ensure that the flask and water are at room temperature. Use the density of water as per the following table for calculations.

 

Temperature (°C)	Density (g mL-1)
22.0	0.99776
23.0	0.99753
24.0	0.99729
25.0	0.99704
26.0	0.99678
27.0	0.99651
28.0	0.99623
29.0	0.99594
30.0	0.99564
31.0	0.99533

REQUENCY OF CALIBRATION

Recommended usage or once in a year 

FORMATS

Format 1: Calibration of Glassware

REFERENCES 

IS 8897: 1978 Reaffirmed 1998

IS 878: 2008

IS 1997: 2008

IS/ISO 4787:2010