Laboratory Balances & Scales - Analytical & Precision | Sartorius (2024)

Readability is the smallest difference in mass that can still be read on a balance/scale.As an example, in the case of an analytical balance, the readability is 0.0001 g.

The ability of a weighing instrument to display corresponding results under constant testing conditions, when the same load is repeatedly placed onto the weighing pan in the same manner. In general, the standard deviation or the difference between the largest and the smallest result for a defined number of measurements is used to specify this quantity.

Some balances are equipped with internal motorized calibrationfunctionfor an easy calibration by one touch.Internal calibrationcan be eveneasierif the balanceisequipped with the isoCAL feature,where internal calibration will be launchedautomatically when environmental conditions change. This feature is very convenient to have in a micro, semi-micro, analytical or precision balance. Depending on the balance readability, usually for 4-,5-,6-and 7-digit balances it is launched every four hours, for lower resolution balances it is every six hours. However, time to time, external calibration is recommended as well. External calibration required more effort on the balance user. In case the calibration may need to be traceable for ISO purposes or to meet other requirement, certified weight should be used to calibrate the balance. A traceable calibration can be done through service from the balance manufacturers (calibration certification), or it can be done by the balance owner if they buyacertified weight which will be used in the calibration process.

Resolution is a term that has not yet been precisely standardized. It is commonly used to express the quotient of the maximum capacity and the readability (“The balance has a resolution of 100,000 digits”) or for readability (“The balance has a resolution of 0.1 g”).

Stabilization time is the time between complete placement of an object / sample on the weighing pan and display of the final result. It can be influenced by setting the appropriate digital filter parameters.

Balances made with PBT plastic parts are chemical resistant and can be cleaned using acetone. Balances that have plastic parts are made of ABS can be cleaned with a damp cloth soaked in water. Be sure to wipe the balance with a soft, dry cloth after cleaning.

Laboratory balances and scales from Sartorius can be used from 5 degreesupto 40 degrees.Mostimportant is that the balance will have performed the internal adjustment for that environment temperature. If it changes, the balanceneed to be adjusted accordingly. Constant temperature is always preferred. Best to have theisoCALset at automatic. This way the balance will always be fit for purpose.

Normally traceable calibrations weights are used. It is widespread, that weights regarding to the OIML R 111-1 are used, which are divided in different classes E1, E2,F1, F2and M1-3with their permissible errors.

TheUnited States Pharmacopeia (USP)Chapter 41 does not reference minimum sample weight any longer, rather it definesrepeatability andaccuracy, which is of crucial importance to determine theoperatingrange of a balance.So,the termminimumweight has been replaced withoperatingrangeminimum. An accuracy of 0.10% is used to calculate this figure.