Calibration of Glass Apparatus SOP

Calibration of glassware as per Indian Pharmacopoeia

• SOP for Calibration of Glassware covers below points:
  • Purpose of Calibration of Glassware
  • Calibration of Volumetric flask
  • Calibration of glass pipette
  • Calibration of burettes
  • Assign identification numbers for Glassware
  • Glassware Calibration format

1.0 OBJECTIVE :

• To provide the procedure for Calibration of Volumetric and Graduated Glass Apparatus.

2.0 SCOPE :

• This procedure applies for Calibration of class ‘A’ and class ‘B’ glass apparatus in Quality Control Department

3.0 RESPONSIBILITY :

• Quality Control Chemist and above

4.0 ACCOUNTABILITY:

• Quality Control Head

5.0 PROCEDURE :

Calibration of glassware means to correct or adjust the graduation of glassware that measure volume.

Volumetric apparatus must be suitably designed to assure accuracy.

The design, construction and the capacity of volumetric Glassware must be in accordance with those laid down by the Bureau of Indian standards.

Volumetric and graduated glass apparatus are grouped as,

• Class ‘ A’ Apparatus
  • – These are procured along with calibration certificate.
  • – On receipt calibrate the glassware before using.
  • – Use in work of the high Accuracy.
• Class ‘ B’ Apparatus
  • – On receipt, calibrate it before using.
  • – Use in routine Work.

All volumetric apparatus are normally calibrated at 27°C.

Pharmacopoeial assays involving volumetric measurements require the use of accurately calibrated glassware.

The tolerance on capacity for volumetric flask, pipette and burettes is laid down in the relevant Indian standards.

5.1 On receipt of glassware allot serial number, label accordingly and then calibrate it.

5.2 Accept only those glasswares which passes in calibration and reject those which not pass in calibration.

5.3 Clean and dry the glasswares before carrying out calibration.

5.4 DENSITY OF WATER (C) :

• Find the weight of empty density bottle (P) in gram.
• Fill the  distilled water up to mark.
• Weigh the density bottle with the distilled water in it (Q).
• Find the weight of water by subtracting the  weight  of the empty density bottle (Q – P).
• Use the weight and volume of the water to calculate density.
• Density of  distilled water  =  Weight(in gram) / Volume (in ml)
• Unit of density is gm/ml.

5.5 FOR VOLUMETRIC FLASKS :

• Weigh clean dried Volumetric flask (A).
• Fill distilled water through funnel 5 mm below the ring mark.
• Adjust the meniscus precisely to ring mark by adding water dropwise with pipette and weigh (B).
• Find out actual weight of distilled water (B-A).
• Find out Volume (in ml) of the flask by following equation,
• Volume (in ml) of the flask =  Actual Weight of distilled water (in gram) / C
• Where, C is Density of distilled water at 27⁰C.
• Measure the volume one time for class ‘A’ and three times for class ‘B’ apparatus and then calculate average (V).
• Find the tolerance by subtracting the specified Capacity from observed Capacity (Volume) of flask.
• It must be within I.P. Standard tolerance Limit.

  VOLUMETRIC FLASKS-Tolerance as per I.P.

Normal Capacity(ml)	5	10	20	25	50	100	250	500	1000
Tolerance, ± ml
Class `A’	0.025	0.025	0.04	0.04	0.06	0.10	0.15	0.25	0.4
Class `B’	0.05	0.05	0.08	0.08	0.12	0.20	0.30	0.5	0.8

5.6 FOR ONE MARK PIPETTES AND GRADUATED PIPETTES :

• Weigh previously dried beaker (A).
• Pipette out distilled water at approx 5 mm above the top mark using pipetting aid.
• Adjust the meniscus precisely by discharging the excess of water up to the mark and transfer to previously dried beaker and weigh (B).
• Find out actual weight of distilled water (B-A).
• Find out Volume (in ml)  of the pipette by following equation,
• Volume(in ml) of the pipette =  Actual Weight of distilled water(in gram) / C
• Where, C is Density of distilled water at 27⁰C.
• Measure the volume one time for class ‘A’ and three times for class ‘B’ apparatus and then calculate average (V).
• Find the tolerance by subtracting the specified Capacity from observed Capacity (Volume) of Pipette.
• It must be within I.P. Standard tolerance Limit.

ONE MARK PIPETTES-Tolerance as per I.P.

Normal Capacity(ml)	1	2	5	10	20	25	50	100
Tolerance, ± ml
Class `A’	0.007	0.01	0.015	0.02	0.03	0.03	0.05	0.08
Class `B’	0.015	0.02	0.03	0.04	0.06	0.06	0.10	0.16

GRADUATED PIPETTES- Tolerance as per I.P.

Normal Capacity(ml)	1	2	5	10	25
Subdivision, ml	0.01	0.02	0.05	0.10	0.20
Tolerance, ± ml
Class `A’	0.007	0.01	0.03	0.05	0.10
Class `B’	0.01	0.02	0.05	0.10	0.20

5.7  FOR BURETTES:

5.8 Assign shelf life after completion of validation.

• Fill the clean dried burette with distilled water to approx 5 mm above the zero mark.
• Remove the air bubble from burette. Set the zero precisely by releasing the water up to zero mark (A).
• Transfer distilled water completely in previously dried and weighed beaker and weigh (B).
• Find out actual weight of distilled water (B-A)
• Find out Volume (in ml)  of the burette by following equation,
• Volume(in ml)  of the burette = Weight of distilled water (in gram) / C
• Where, C is Density of  distilled water at 27⁰C.
• Measure the volume one time for class ‘A’ and three times for class ‘B’ apparatus and then calculate average (V).
• Find the tolerance by subtracting the specified Capacity from observed Capacity (Volume) of Burette.
• It must be within I.P.  Standard tolerance Limit.

BURETTES- Tolerance as per I.P.

Normal Capacity(ml)	10	25	50	100
Subdivision, ml	0.05	0.05	0.10	0.20
Tolerance, ± ml
Class `A’	0.03	0.03	0.05	0.10
Class `B’	0.05	0.05	0.10	0.20

5.8 ASSIGN GLASSWARE IDENTIFICATION NUMBER

• Affix the tag to glassware with ID number after calibration.
• For all calibrated glassware assign ID number as below,
• CAL/QC/X/Y-Z
• Where,
  • CAL  – Calibration
  • QC  – Quality Control
  • X   – Code for glassware as mentioned below,
    • VF  – for Volumetric Flask
    • P    – for one mark pipette
    • GP  – for Graduated pipette
    • BR  – for burette
  • Y – Actual volume (in ml)
  • Z – Serial Number starting from 01
• Write the remark in format for glassware calibration in case of breakage of glassware.
• Replace the new glassware with same Identification Number in case of breakage.
• Calibrate the glassware’s yearly.
• Maintain the record of calibration up to 5 years.

 6.0 ABBREVIATIONS:

Abbreviation	Expanded form
I.P.	Indian Pharmacopoeia
0C	Degree Centigrade
gm	Gram
ml	Milliliter
ID	Identification
approx	Approximately
mm	Millimeter

7.0 ANNEXURES:

Annex . No.	Title
01	Glasswares Calibration

8.0 SOP REFERENCES

•  Indian Pharmacopoeia 2018

END OF THE SOP

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ANNEXURES :

Annex. No. 01 Glasswares Calibration

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