LimsPulse
Physical testing

Analytical balance

Measures the mass of a sample very precisely, usually to 0.1 mg or 0.01 mg. Almost every quantitative test in a QC lab starts with a weighing, so the balance is the most used instrument in the lab.

  • Pharmaceutical
  • Biotech
  • Chemicals
  • Food & beverage
  • Academic research
  • Cosmetics
Photo of a Analytical balance
Photo: Karelj, Public domain (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the calibration status label and that today's daily check has been done and recorded.
  2. 2Check the levelling bubble is centred. If not, level the balance and record it.
  3. 3Make sure the balance has been switched on (or on standby) long enough to warm up, commonly at least 30 minutes, or as the manufacturer states.
  4. 4Clean the pan and the chamber with a soft brush.
  • Do not use a balance that has been moved, is not level or is past its calibration due date.
STAGE 2

Weighing

  1. 1Close the draught shield doors and press zero.
  2. 2Place a clean, dry weighing container (boat, butter paper or weighing bottle) in the centre of the pan and press tare.
  3. 3Add the sample with a clean spatula, keeping the doors closed as much as possible.
  4. 4Close the doors and wait for the stability indicator before recording the reading.
  5. 5Print the weight or send it to the LIMS; do not write it from memory.
  • Never weigh a sample below the balance's minimum weight.
  • Let hot or cold items reach room temperature first; warm objects read low because of air currents.
  • Use an anti-static device for dry powders that cling to the container.
STAGE 3

Weighing by difference

  1. 1Weigh the closed weighing bottle containing the sample and record the mass.
  2. 2Transfer the required portion into the flask.
  3. 3Re-weigh the bottle. The difference between the two weights is the mass transferred.
  • This method is preferred for hygroscopic samples and for transfers where powder may stick to the container.
STAGE 4

After use

  1. 1Remove the container and clean any spilled material from the pan and chamber.
  2. 2Close the doors and leave the balance on standby rather than switching it off.
  3. 3Complete the balance usage log.
  • Clean potent or toxic powder spills immediately and as your safety procedure describes.
In LimsPulse · Calibration Management

Keep every Analytical balance in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how