What is the difference between an analytical balance and a precision balance?

An analytical balance provides readability of 0.1 mg or better, while a precision balance typically reads to 0.001 g or 0.01 g. Analytical balances include draft shields and are designed for highly sensitive measurements. Precision balances handle larger samples and are less affected by environmental conditions.

What readability do I need for my lab application?

You need a readability that is at least one-tenth of your smallest sample weight or required measurement increment. For example, measuring 100 mg samples may require 0.01 mg readability, while gram-level work may only need 0.01 g. Selecting higher readability than necessary increases cost without improving results.

Do lab balances need to be calibrated?

Yes, all lab balances require regular calibration to maintain accuracy. Calibration ensures measurements remain traceable to certified standards. Internal calibration simplifies this process by automating adjustments, while external calibration requires manual verification with certified weights. In regulated environments, calibration records must be documented and retained.

What is the difference between readability and repeatability?

Readability is the smallest increment of weight a balance will display. Repeatability is the degree of agreement between multiple measurements of the same mass, on the same balance, under the same conditions.

What is the best way to clean my balance to ensure accurate readings?

Inspect and clean before each use. A flannel cloth or soft brush works well for dusting and light cleaning. Use a non-abrasive cleaner for light spills, and a dry flannel cloth for glass parts. Set a regular maintenance schedule for deep cleaning to ensure optimal performance and instrument longevity.

Can vibration affect the accuracy of my balance?

Yes — even slight vibration from a heavy footstep can affect accuracy. Place the balance on a sturdy benchtop away from high-traffic areas such as hallways, elevators, stairways, and doors. If that placement is not possible, an anti-vibration table should be considered.

Taxing Your Knowledge of Lab Equipment: Take the Tech Challenge

On a day known for taxing us, let’s add one more challenge.

Chemical Compatibility with a Plastic Desiccator

HygroscopINC generally uses large plastic vacuum desiccators (greater than 20 L and up to 28.5″ Hg vacuum pressure) to keep water from reentering its hygroscopic chemicals as they cool from 500ºF. However, they have noticed the plastic starting to crack and fissure when used to cool one of the newer chemicals. They suspect the plastic of their desiccator is not compatible with the fumes of their new chemical, and this is the cause of the fissures inside the plastic desiccators.

They have not noticed any problems with the glass bottles storing the chemical or the silicone and neoprene gaskets on their desiccators, or the metal liner of the caps on the storage bottles. Outside of the glass and the thin stainless steel liner of the caps (silicone and neoprene), they do not have any chemical compatibility data. They are looking for a few desiccators that would be compatible with their newest chemical to replace the fissured plastic units.

What would you suggest?

Glass/Stainless Steel Desiccator with Two Stainless Steel Shelves (08901-60).
The 250-mm Pyrex® Glass Vacuum Desiccator (34548-29).
A vacuum oven with a stainless steel interior (such as the
1.8 cu ft Salvis® Vacucenter Oven 52402-10).

See answers below

Glass/Stainless Steel Desiccator with Two Stainless Steel Shelves (08901-60).
Correct! This desiccator has a high capacity interior and is made of parts that are already known to be compatible with the new chemical.
The 250-mm Pyrex Vacuum Desiccator (34548-29).
Incorrect. Based on the large volume the customer needs the desiccator to hold, this unit will not be sufficient. It has only a 10.5 L capacity.
A vacuum oven with a stainless steel interior (such as the
1.8 cu ft Salvis Vacucenter Oven 52402-10)
Incorrect. Although this option would satisfy the internal capacity and chemical compatibility issue, it is overkill. A much more economical alternative exists.

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