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.
Weighing is one of the most common, critical tasks and time-consuming tasks in the laboratory, therefore, weighing the right way is crucial.
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. Moreover, the touchscreen digital display makes the operation of the balance intuitive.
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
- Environmental vibrations
- Magnetism effects
- 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 the most common factors affecting weighing accuracy and to explain the basic rules of weighing the right way with laboratory balances. This guide begins with suggestions for the optimum location of a balance. It then describes the proper operation of this sensitive instrument, before analyzing possible external influences and their effects. Most of these influences are recognizable by a slow change in the weight display (drift).
Technologically advanced balances allow laboratory professionals to perform weighing faster and smarter, even without having to use a special weighing room.
Nevertheless, weighing results are still prone to inaccuracies, due to:
The influence of external factors (e.g. airflow, magnetism, electrostatic forces).
Misinterpreting sample characteristics for external influences
Faulty operation of the balance
Choosing an inappropriate location for the balance
Incorrect interpretation of technical data
Following METTLER TOLEDO “Weighing the Right Way” guidelines will help you understand which are the factors affecting weighing accuracy and how to minimize the possibility of making a mistake during the weighing process.
Save time and get your weighing results right the first time.