Electric Weighing Balance

Standard Operating Procedure (SOP) for Electric Weighing Balance

1. Purpose:

To provide a standardized method for operating and maintaining the electric weighing balance to ensure accurate and reliable measurements.

2. Scope:

This SOP applies to all personnel involved in the use of the electric weighing balance in the laboratory for weighing samples and reagents.

3. Responsibility:

  • Laboratory Technicians: Operate the electric weighing balance as per the SOP.
  • Lab Manager: Ensure the SOP is followed and updated as needed.

4. Equipment and Materials:

  • Electric Weighing Balance
  • Calibration weights
  • Personal Protective Equipment (PPE): Lab coat, gloves, safety goggles
  • Weighing boats, papers, or containers
  • Cleaning brush or lint-free cloth

5. Procedure:

5.1 Pre-Operation:

  1. Ensure the weighing balance is on a stable, vibration-free surface, away from drafts, direct sunlight, and magnetic fields.
  2. Check the balance for cleanliness and ensure the weighing pan is free of dust and residues. Use a cleaning brush or lint-free cloth if needed.
  3. Wear appropriate PPE before starting the procedure.

5.2 Calibration:

  1. Turn on the weighing balance and allow it to warm up
  2. Press the tare button to zero the balance.
  3. Place a calibration weight on the center of the weighing pan.
  4. Compare the displayed weight with the known weight of the calibration mass. If the balance does not display the correct weight, recalibrate according to the manufacturer’s instructions.
  5. Repeat the calibration process with different weights to ensure accuracy across the balance’s range.
  6. Remove the calibration weight and press the tare button to zero the balance again.

5.3 Weighing:

  1. Place a clean weighing boat, paper, or container on the weighing pan.
  2. Press the tare button to zero the balance, accounting for the weight of the container.
  3. Add the sample or reagent to the container. Ensure the added material does not exceed the balance’s capacity.
  4. Wait for the reading to stabilize and record the weight.
  5. Remove the container and sample from the balance.

5.4 Post-Operation:

  1. Clean the weighing pan and surrounding area using a cleaning brush or lint-free cloth to remove any residues.
  2. Turn off the weighing balance if it will not be used for an extended period.

5.5 Maintenance:

  1. Regularly inspect the balance for signs of wear or damage.
  2. Clean the balance frequently to prevent buildup of residues and ensure accurate measurements.
  3. Perform routine calibration checks as specified by the manufacturer or lab protocol.
  4. Record maintenance activities in the equipment logbook.

6. Safety Measures:

  1. Handle all samples and reagents with care, following safety guidelines.
  2. Ensure proper ventilation in the area where the weighing balance is used.
  3. Dispose of waste materials and residues according to the laboratory’s waste disposal guidelines.

7. Documentation:

  1. Record the date, time, and purpose of each use in the weighing balance logbook.
  2. Note any deviations from the SOP and report them to the lab manager.

8. References:

  • Manufacturer’s Manual for the Electric Weighing Balance
  • Laboratory Safety Guidelines
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