Overview
This lecture explains the use, setup, operation, and cleaning of an analytical balance in a biotech laboratory, including best practices for accurate measurements.
Analytical Balance Basics
- An analytical balance measures very small masses with precision up to four decimal places.
- Typical maximum capacity is 310 grams; exceeding this can damage the balance.
- The balance is sensitive to vibrations and air currents, so placement is important.
Proper Setup and Use
- Place the balance on a steady, level surface away from doorways or vents.
- Adjust the feet so the air bubble is centered in the black ring to ensure the balance is level.
- Let the balance warm up if it was turned off or unplugged.
Weighing Procedure
- Use weighing paper for measuring masses under 5 grams; fold paper to help contain samples.
- Place paper or weigh boat on the pan, close side doors, and press tare to zero.
- Add substance slowly using a lab scoop, closing the doors to stabilize readings.
- For accurate measurement, ensure the balance reading is locked in before recording the weight.
- Maintain measurement accuracy within specified tolerances (e.g., ±0.02 grams for Tris buffer).
- Always record all measurements in the lab notebook.
Cleaning and Maintenance
- Clean the balance at the end of each day or after use.
- Put the balance in standby mode or unplug before cleaning.
- Remove the pan and use a soft brush to sweep away any remaining powders.
- Clean grooves and replace all components after cleaning.
Key Terms & Definitions
- Analytical balance — A precision instrument used to measure small masses to four decimal places.
- Tare — To zero the balance, subtracting the weight of containers or weighing paper.
- Weigh boat — A container used to hold larger or bulkier samples on a balance.
- Weighing paper — Specially folded paper used to hold powders under 5 grams.
- Lab notebook — An official record where all measurements and procedures are documented.
Action Items / Next Steps
- Practice using the analytical balance following the outlined procedures.
- Document all measurement activities in your lab notebook.
- Clean the analytical balance after use.