SOP for Cleaning, Calibration and Verification of Volumetric Glassware for Accuracy

SOP for Cleaning, Calibration and Verification of Volumetric Glassware for Accuracy

1.0 Objective

To lay down the procedure for Cleaning ,calibration and verification of volumetric glassware to ensure accuracy and reliability of analytical results.

2.0 Scope

This SOP is applicable to the Quality Control Department for calibration of volumetric glassware.

3.0 Responsibility

• Analytical Chemist shall be responsible for performing Cleaning ,calibration and adhering to this SOP.

4.0 Accountability

• Department Head and QA Head shall be accountable for implementation and compliance of this SOP.

5.0 Abbreviations and Definitions

• SOP: Standard Operating Procedure
• QA: Quality Assurance
• QC: Quality Control

6.0 Procedure

6.1 Classification of Glassware

• Class ‘A’ Glassware:

  Used for analytical purposes and supplied with calibration certificate. No in-house calibration required (only verification if needed).

• Class ‘B’ Glassware:

  Requires in-house calibration before use.

6.2 Identification of Glassware

On receipt of Class ‘B’ glassware, assign identification numbers as follows:

• Volumetric Flask: VF-01, VF-02…
• Transfer Pipette: TP-01, TP-02…
• Burette: BT-01, BT-02…

6.3 Cleaning Procedure

6.3.1 Clean glassware thoroughly before calibration.
6.3.2 Immerse glassware in chromic acid solution for 30 minutes to remove grease and dirt.
6.3.3 Rinse under running tap water followed by rinsing twice with deionized water.
6.3.4 Dry the glassware in hot air oven at 60–65°C for 60 minutes.
6.3.5 Remove and allow to cool in a desiccator at 25°C ± 2°C.

6.4 Calibration Procedure for Class ‘B’ Glassware

6.4.1 General Requirements

• Use purified water maintained at 25°C ± 0.5°C
• Perform calibration at ambient temperature 23°C to 27°C
• Perform calibration in triplicate

6.4.2 Calibration of Volumetric Flask

1. Weigh the clean, dry empty volumetric flask (W1).
2. Fill the flask with purified water up to the calibration mark.
3. Wipe the outer surface dry.
4. Weigh the filled flask (W2).
5. Calculate weight of water:

   Weight of water = W2 – W1

6. Calculate volume using correction factor:

   1 mL water at 25°C = 0.99602 g

7. Record observations in Annexure-I.

6.4.3 Calibration of Pipette and Burette

1. Weigh a clean, dry empty beaker (W1).
2. Fill pipette/burette with purified water up to the mark.
3. Transfer water into pre-weighed beaker.
4. Weigh the beaker with water (W2).
5. Calculate weight of water:

   Weight of water = W2 – W1

6. Calculate volume using correction factor:

   1 mL water at 25°C = 0.99602 g

7. Record observations in Annexure-I.

6.4.4 Calculations

• Calculate average observed volume from triplicate readings.
• Calculate difference using formula:

Difference in Volume = Labeled Volume – Average Observed Volume

6.4.5 Acceptance Criteria

The difference between labeled and observed volume shall comply with tolerance limits given in Table-I.

6.5 Table-I: Glassware Tolerance Limits

Volumetric Flask

Transfer Pipettes

Burettes

6.6 Precautions

• Ensure water temperature is between 23°C to 27°C
• Maintain water bath at 25°C ± 0.5°C
• Avoid parallax error while reading meniscus
• Ensure glassware is completely dry before weighing

7.0 Frequency

Calibration shall be performed quarterly.

Cleaning Procedure of Glassware

1.0 Objective

To lay down a procedure for proper cleaning of glassware to prevent contamination and ensure accuracy and reliability of analytical results.

2.0 Scope

This SOP is applicable to all glassware used in the Quality Control and Microbiology laboratories.

3.0 Responsibility

• QC/Microbiology Analyst: Responsible for cleaning glassware as per this SOP
• Laboratory Supervisor: Ensure compliance with the procedure

4.0 Accountability

• Department Head and QA Head shall be accountable for implementation of this SOP

5.0 Abbreviations and Definitions

• SOP: Standard Operating Procedure
• QA: Quality Assurance
• QC: Quality Control

6.0 Procedure

6.1 General Requirements

• Clean glassware immediately after use
• Use appropriate cleaning agents based on type of residue
• Avoid scratching or damaging glassware
• Ensure complete removal of detergents and residues

6.2 Routine Cleaning Procedure

1. Rinse the glassware with tap water immediately after use to remove soluble residues
2. Wash with suitable laboratory detergent using a brush (if required)
3. Rinse thoroughly with running tap water to remove detergent
4. Rinse at least 2–3 times with purified/deionized water
5. Allow to drain excess water

6.3 Cleaning for Greasy or Stubborn Residues

• Soak glassware in chromic acid cleaning solution for 30 minutes
• Alternatively, use suitable non-chromic cleaning agents (as per safety policy)
• After soaking:
  • Rinse thoroughly with tap water
  • Follow with purified water rinsing (2–3 times)

6.4 Final Rinse

• Final rinse should always be done with purified or distilled water
• For critical analysis, use double distilled or deionized water

6.5 Drying Procedure

• Air dry in dust-free environment OR
• Dry in hot air oven at 60–65°C
• Ensure glassware is completely dry before use or storage

6.6 Storage

• Store clean glassware in designated clean cabinets or racks
• Keep covered or inverted to prevent contamination
• Segregate clean and used glassware

6.7 Special Precautions

• Do not use cracked or damaged glassware
• Avoid direct contact of hands with critical surfaces
• Use PPE: gloves, lab coat, safety goggles when handling chemicals
• Handle chromic acid with extreme care (corrosive and hazardous)

6.8 Verification of Cleanliness

• Visually inspect for:
  • Absence of stains, grease, or residues
  • No water droplets (for dry glassware)
• If required, perform rinse water conductivity/pH check

7.0 Frequency

• After every use
• Before calibration or critical analysis

8.0 Forms and Records

• Annexure-I: Calibration Record of Glassware
• Annexure-II:Glassware Cleaning Log

9.0 Distribution

• Master Copy: Quality Assurance
• Controlled Copies: Quality Control

10.0 History