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:
- Ensure the weighing balance is on a stable, vibration-free surface, away from drafts, direct sunlight, and magnetic fields.
- 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.
- Wear appropriate PPE before starting the procedure.
5.2 Calibration:
- Turn on the weighing balance and allow it to warm up
- Press the tare button to zero the balance.
- Place a calibration weight on the center of the weighing pan.
- 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.
- Repeat the calibration process with different weights to ensure accuracy across the balance’s range.
- Remove the calibration weight and press the tare button to zero the balance again.
5.3 Weighing:
- Place a clean weighing boat, paper, or container on the weighing pan.
- Press the tare button to zero the balance, accounting for the weight of the container.
- Add the sample or reagent to the container. Ensure the added material does not exceed the balance’s capacity.
- Wait for the reading to stabilize and record the weight.
- Remove the container and sample from the balance.
5.4 Post-Operation:
- Clean the weighing pan and surrounding area using a cleaning brush or lint-free cloth to remove any residues.
- Turn off the weighing balance if it will not be used for an extended period.
5.5 Maintenance:
- Regularly inspect the balance for signs of wear or damage.
- Clean the balance frequently to prevent buildup of residues and ensure accurate measurements.
- Perform routine calibration checks as specified by the manufacturer or lab protocol.
- Record maintenance activities in the equipment logbook.
6. Safety Measures:
- Handle all samples and reagents with care, following safety guidelines.
- Ensure proper ventilation in the area where the weighing balance is used.
- Dispose of waste materials and residues according to the laboratory’s waste disposal guidelines.
7. Documentation:
- Record the date, time, and purpose of each use in the weighing balance logbook.
- 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