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Posted on Tue, Mar 19, 2013

Guaranteeing Time Stable Biomagnetic Separation Conditions

Magnet quality has to be considered in magnetic bead separationOf course, as in most industries, product consistency is key to the success of the Life Sciences industry. With magnetic bead separation, not only should working conditions be constant over time, but conditions should also be consistent from lot to lot, regardless of the time between production runs. One thing that should always be considered is the quality of the magnet used in the biomagnetic separation devices.

 

This post is about magnetic bead separation and how to validate this process. If you are interested in this topic, and are willing to learn more about it, download our Free Guide The Starting Guide to Validate Biomagnetic Separation Processes:

 

Free PDF guide:   "Validation of Magnetic Bead Separation Processes" 

 

Magnetic bead separation with rare earth magnets

 

Modern separation devices use Rare Earth permanent magnets as the magnetic field sources. The normal assumption is that ‘permanent’ magnet properties are ‘permanent’ and constant over time, however these magnets can be demagnetized under certain conditions that are achievable in a lab situation. It is vitally important that production managers understand and avoid these adverse lab conditions in order to properly maintain their magnetic sources.

 

Permanent magnets (i.e. Rare Earth) can be demagnetized if they are exposed to magnetic fields of more than 2T. A field of 2T is nearly five orders of magnitude greater than the Earth’s magnetic field. Superconducting coils found in devices such as an MRI or in an Intense Pulsed Magnetic Field machine can achieve these values. Therefore, the biomagnetic separator should not be put in the working volume of this devices, when magnetic field can be high enough to demagnetize it.

 

Permanent magnets can be demagnetized for magnetic bead separation when exposed to fields greater than 2T

Permanent Rare Earth magnets can also be demagnetized when exposed to temperatures greater than 80ºC. Under normal temperature fluctuations, magnetization can also vary, but only slightly and the effect is reversible. Between 20 and 40ºC, for example, the magnetic forces can decrease from 2-3%. If the lab temperature is not controlled, magnetic forces will reversibly drop approximately 0.1% per each ºC increase in temperature. When temperatures are greater than 80ºC, however, the changes in magnetization can be irreversible.

Avoiding these two conditions in the lab will guarantee a long life for your biomagnetic separation device.

 

If you found this article interesting and want to get a deeper insight in the topic of magnetic bead separation, make sure to check these articles from our blog:

Dr. Lluís Martínez

biomagnetic separation processes

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