Weighing the right way

Factors affecting weighing accuracy can negatively influence the results of the whole analysis, therefore it is important to be aware of the rules that need to be followed when working with laboratory balances.

Balances have developed to the point that, in general, no special weighing room is necessary, except maybe for ultra-micro balances.

Technological advances in electronics have considerably simplified the operation of balances, reducing weighing times. However, this apparent ease of use can lead to insufficient care being taken to avoid the negative influence on analyses results caused be multiple factors affecting weighing accuracy. External influences are defined as physical effects which are measurable for all laboratory balances. Examples of external influences include:

• Electrostatic forces
• Airflow
• Environmental vibrations
• Magnetism effects
• Evaporation
• Moisture uptake

Certain sample characteristics could also be mistaken for external influences – such as evaporation of liquids, or hygroscopic/hydrophobic solid materials gaining or losing weight.

The purpose of this guide is to identify most common factors affecting weighing accuracy and to explain the basic rules of weighing the right way with laboratory balances