Analytical Balances are extremely accurate balances design to precisely measure the mass of an object.
Key points while using Analytical balances:
1) Ensure that Balance is placed on firm, vibration free surface, preferably in low traffic area, away from Air conditioning System and windows as direct sunlight can lead to drift due to temperature changes.
2) Check for Balance Calibration Status (Daily, Monthly and Quarterly schedule).
3) Check the leveling bubble, if the bubble is not centered, adjust the feet of the balance until the bubble is centered by rotating both feet in desired direction.
4) Ensure to use balance of proper operating range, the weight range within which it will provide accurate readings. Suppose weighing capacity of Analytical balance is 0.02g to 2.00g, here 0.02g is minimum operating value and 2.0 g maximum operating value.
5) Before weighing make sure to clean the balance pan to prevent contamination, use a tissue or a lint free cloth to remove dust and powder. (Don’t use abrasive material to clean the balance pan and also don’t blow at the balance to remove powder or dust as this could cause it to get inside the balance).
6) Never weigh chemicals directly on the balance pan. Instead, use a suitable weighing vessel, weighing paper, or filter paper.
7) Use clean gloves or forceps or tweezers while weighing the sample on pan, don’t touch sample or weighing paper or vessel with bare hands as it may lead to contamination.
8) Always ensure to carry out the weighing at the center of pan and make sure to close the door while weighing (as it protects the balance from external influences that can cause inaccurate readings).
9) Never weigh Hot or cold sample directly on analytical balance because the weight reading will be inaccurate as hot sample will appear lighter than they actually are due to air buoyancy and Cold sample will appear heavier than they actually are due to water vapor condensation.
10) Weighing of Hygroscopic Material:
a) Weigh the material directly in a glass vessel and then dissolve with suitable diluent and transfer (Suitable mostly in case of buffers).
b) Weigh directly in reaction flask.
c) Use narrow neck weighing vessel.
d) Ensure to use Stopper or cover.
e) Maintain proper Humidity in weighing room for quick stability. (Lower humidity).
11) Weighing of Liquid sample: Liquid standard or sample should be directly weighed in Erlenmeyer flask sealed with the stopper or volumetric flask to prevent evaporation.
12) An additionally also ensure to check readability of Analytical Balance i.e the smallest weight or increment that the balance can display. (It’s basically number of digits displayed after decimal point).
Read also: Why Air Bubble Adjustment is Important for Analytical Balance?
