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.

Getting False pH Readings | from Cole-Parmer Blog

A chemical manufacturer was losing raw materials to what workers thought were erroneous pH readings. The manufacturer has a pH control system that activates a solenoid valve in the bottom of the tank once a specific level is reached.

Shortly after the tank started emptying, the workers saw the pH spike—and manually shut off the valve and scrapped the batch. After this happened a few times, they began rechecking the pH of the raw material. They found it measured exactly where it was supposed to be. They even double checked the measurement with a separate tester.

So, they requested a warranty replacement on the pH probe. After troubleshooting, they found it was actually the solenoid valve that was starting to go bad. As the valve wore out, stray electrical signals entered the mixing tank and the probe interpreted the stray signal as a change in pH.

What’s the best way to avoid erroneous readings from stray voltages in the future? A solution-grounded pH probe will combat electrical interference. The addition of a ground wire will allow any stray electrical signals in the solution to go to the grounding wire rather than the probe—eliminating any unstable or inaccurate readings.

See our full selection of pH meters and water quality products and In-line or Submersible, Solution Grounded pH/ORP Electrodes. Or check out our best selling Oakton^® EcoTestr^™ Pocket pH tester.

Getting False pH Readings

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