Analytical Balance Best Practices

It doesn’t take much to throw an analytical balance off.  What are the analytical balance best practices to keep your balance without error. The opportunities for errors to occur increase dramatically as the resolution or readout of analytical balances increases.  That’s why labs and other users of an analytical balance should establish and post a “best practices” list and remind researchers to employ them at all times.

Once again we refer to the operations manual supplied with analytical balances such as the Kern series offered by Tovatech.  These multi-page manuals, however, are not always “user friendly” although most instructions regarding to-do-or-not-to-do are published in the setup pages.  Here we provide a brief analytical balance best practices bulletin to serve as a reminder.  They are in no particular order of importance because all are important.

That said, a key point to remember is that sensitive balances are sensitive to many extraneous influences – the environment where they are employed.

  • Temperature.  Balances are designed to operate within what is called permissible ambient temperatures such as 18⁰ to 30⁰C.  But what they do not like are variations in temperature once they acclimate to the lab’s ambient temperature.  Drafts from windows, HVAC vents, opening and closing doors, and exposure to direct sunlight cause unwelcome variances.   Some analytical balances such as the Kern ABT models provide an automatic adjustment if there is a temperature variation greater than 0.5⁰C.  Others do not.
  • Vibration.  An ideal location for an analytical balance is in a concrete floored basement of the lab.  This is not always practical so position the balance on a sturdy countertop away from high-traffic areas.  If an ideal vibration-free location cannot be obtained use a weighing table that absorbs vibrations.
  • A level balance is a happy balance.  That’s why they come equipped with a leveling bubble and adjustable foot screws.
  • Electrostatic charge, especially when weighing dry non-conductive samples, can cause weighing errors.  A discharge ionizer positioned next to the balance solves the problem.
  • Shut the door!  Analytical balances are equipped with doors that isolate the weighing pan from the lab environment, no matter how perfect it may be (#1 above). Even breathing on the sample during weighing can introduce errors.
  • Wear gloves.  Fingerprint oils on tared sample pans likewise lead to incorrect readings.
  • A clean balance is a happy balance. Remove spilled samples immediately with a brush or gentle vacuuming.  Use water for water-miscible liquids and an appropriate solvent for other liquids.
  • Establish and post a calibration schedule.  This is crucial to weighing accuracy.  Some models such as the ABT mentioned above self-calibrate on a regular basis (every 4 hours in this case).  Others are internally or externally calibrated using easy to understand instructions and, in the case of externally calibrated units, the correct calibration weight.

More information on this topic can be obtained by downloading our buyers guide to digital scales.

Rely on the scientists at Tovatech for unbiased assistance in selecting and operating an analytical balance that meets your weighing requirements.  We invite you to contact us with your questions.

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More