Using an Analytical Lab Balance
The first step is to prepare the balance for weighing your sample, by leveling and zeroing it. Check whether the leveling bubble on the weighing chamber’s floor is centered, or adjust the leveling screws located underneath. Then, close the chamber doors and briefly press down on the control bar till a row of zeros is displayed.
Solid objects can be weighed directly on the balance pan, by opening the chamber doors and placing the object on the pan. The readout will be displayed after you close the doors.
Use the appropriate container for weighing liquids, powders, or granular substances. Start by placing the container on the pan and zeroing the balance. Then, carefully add the sample (either directly, or by removing the container and making sure the control bar is untouched), close the doors and check the readout.
If any chemicals have spilled on the balance, it should be cleaned thoroughly. Shut it down (by gently raising the control bar) after you’re done using with your weighing procedures for the day.
These sensitive devices are easily affected by air currents, temperature and other physical variables, so they are enclosed or shielded to reduce exposure. Still, the enclosures will not be able to protect them completely.
Best Location for an Analytical Balance
These sensitive devices are easily affected by air currents, temperature and other physical variables, so they are enclosed or shielded to reduce exposure. Still, the enclosures will not be able to protect them completely.
You need to ensure they’re placed in a secure location that is quiet, clean, temperature-controlled and draft-free.
If the building floor isn’t level, the analytical scale should be placed near an outside wall to reduce misalignment issues.
They should be placed on a sturdy and level weighing table, with a cork or rubber layer to absorb vibrations.
For higher accuracy and readability, use a balance with a self-correct feature or additional filters against physical influences.
Physical Influences and Calibration
Analytical balance readouts can be affected by changes in the sample and/or container as well as other physical influences.
Use clean and dry containers for samples, and avoid beakers with large or wide openings. Pick the smallest container possible, and cover it if needed.
Condition the sample/container to the prevailing temperature, to avoid issues with repeatability and weighing results. You may also find drifts in the readout value (even with a stable display when the balance isn’t loaded) otherwise.
Evaporation may occur in uncovered samples/containers, or they may absorb water if handled with bare fingers. Readouts could increase or decrease continuously, or you may find drift (even with a stable display when the balance isn’t loaded).
Electrostatically charged samples/containers (e.g. glass or plastic) or very low humidity may cause non-repeatable values or drifts in one direction. Shield the sample with metal foil or a metal container, increase the humidity and neutralize static electricity with an ionizing blower.
