Improve Precision Scale Accuracy by Negating Electrostatic Charge

When using precision digital scales and analytical balances to measure in grams and milligrams it does not take much to throw off a reading.  Something seemingly as innocuous as an electrostatic charge, for example, can yield inaccurate results.  This usually occurs when non-conductive materials are being weighed – such as plastic, china and glass.  Because they can carry an electrostatic charge an electromagnetic field can be generated between the goods being weighed and the precision balance or scale. This can impact accuracy by as much as a gram.

In many instances a gram does not seem to be much. This is not true when you’re weighing in milligrams or smaller increments. A case in point: I used to work with lyophilized (freeze-dried) polysaccharides such as guar gum, locust bean gum, and xanthan gum.  After freeze drying, these materials were light and fluffy in the extreme and just loaded with static charge.  It was nearly impossible to transfer sample from the container to the balance and from the balance to my beaker without the material flying all over the place.

In these cases the electrostatic charge must be neutralized using a discharge ionizer such as the Kern AC-Korona.  This handy gadget can be mounted next to the balance or you can manually direct it from all sides toward the items being weighed. This simple precaution enhances the accuracy of your operations.

In my case I mounted the discharge ionizer near my balance, and like magic I could transfer and weigh my samples.

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What experiences have you had dealing with static electricity?  How were they overcome?  Please share some examples.

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