Operating Procedure for Weighing Balances

Weighing range: 0.001 g to 220.000 g.
All the weighing activities to be performed on this balance should be within or equal to the above range.
Whenever there is a need of “Accurate Weighing” below 1.000g, then do not use this balance.

Prerequisites for performing weighing

1. Assemble the proper equipment, such as containers for weighing, receiving vessels, forceps, pipettes, spatulas of proper size, butter papers etc.
2. Use containers of such size that the loading capacity of the balance is not exceeded.
3. Make sure that the container selected is dry & clean.
4. Materials, which are refrigerated, take care to bring them to room temperature prior to perform weighing.

Related: Calculation for Determination of Weighing Range of Balances

Balance environment

1. Check balance level on spirit level indicator (level can be adjusted by screws provided on the bottom backside).
2. Check balance for cleanliness.
3. If the balance is not cleaned, clean it with a soft brush.

Related: Drift and Its Importance in Analytical Balances

Balance Calibration

1. Before performing weighing assure that, balance is calibrated.
2. If during or before weighing power supply fails, then recalibrate the balance.
3. Check that all the connections of the balance are proper & balance is ON.
4. Ensure that balance is kept on a shockproof bench top.
5. If the balance is showing some reading on the display then (ensure that nobody requires that reading) press tare key.
6. Balance should show 0.000.
7. Open the door from one side & keep container or sampling bag as required & close the door & press tare key.
8. Then open the door & put required sample.
9. Add sample till you get desired weight on display & close the door.
10. After getting a stable display, open the door & take out the sample with container or sampling bag.
11. Close the door & press tare key again.

Related: Analytical Balance Calibration

PRECAUTIONS

1. To clean the balance use soft brush.
2. Remove pan & its housing carefully if required (for cleaning).
3. Clean with damp cloth.
4. Do not blow air into the chamber under any circumstances.
5. Never press or touch the weighing pan during weighing.
6. Always close or open the balance doors gently.

REFERENCE

Indian Pharmacopoeia.
United States Pharmacopeia.