Electronic balances are highly valued measuring equipment for chemical, analytical and formulation operations in quality industries and laboratories. They are used, like scales in general, to measure the mass of a body or substance, only that as this is a precision balance, the measurement is exact.
What should you keep in mind?
To weigh correctly on a laboratory balance, it is necessary to take into account the possible sources of error and act to avoid or minimize them. Despite the perfection achieved in balance manufacturing, disruptive environmental effects and poor practice can result in weighing errors.
What are the most common mistakes when using a balance?
- Use the cell phone in the weighing cabin
- The analysts of the eighties or nineties did not have this problem, but with the massification of cell phone use it has become a real problem, and it is not only because of the electromagnetic radiation it emits, but also causes loss of attention in the analyst.
- Using the scale out of level
Many times due to ignorance, eagerness or simple laziness, we ignore the verification of the level of our balance and consequently the measurement carried out is not reliable.
- Not respecting the environmental conditions
To establish the temperature and relative humidity levels, the correct thing to do is go to the manufacturer’s manual for each piece of equipment and based on the recommendations established therein, the environmental conditions of each area should be set.}
- Use the balance on unstable or vibrating tables
You must bear in mind that laboratory balances are such sophisticated equipment, that anything that moves will be interpreted in the equipment as a variation in weight, therefore you must place the balance on a stable, antimagnetic table, protected against static charges and single fixation.
- Weigh hygroscopic substances without due precaution
Hygroscopic substances absorb humidity from the environment causing the reverse effect of evaporation (weight gain). The way to minimize this effect is to have the substance with its container in a desiccator with the active drying agent.
- Not respecting the heating time
Again, due to eagerness or ignorance, the balance is used without waiting for the prudent warm-up time. Balances and all electronic equipment in the laboratory have a warm-up time specified by the manufacturer, respecting the warm-up time indicated in the manual is necessary to establish the balance’s thermal balance.
- Weigh very hot substances
When you put a hot substance on the balance, a temperature difference is generated between the sample and the environment of the measurement chamber, which causes air currents. These air currents generate forces on the measuring plate making the sample appear lighter (known as dynamic fluctuation) .This effect only disappears when thermal equilibrium is reached. This makes a cold object appear heavier, or a hot object appear lighter.
- Weigh substances in the presence of electrostatic charges
Electrostatic charges are formed by friction or during the transport of materials, especially if they are in granules or powder. If the air is dry (relative humidity less than 40%) these electrostatic charges are retained or are slowly dispersed. Measurement errors occur due to electrostatic attractive forces that act between the sample and the environment.