Although **separation time** may be one of the most obvious parameters to validate in your **magnetic separation rack** production, it is certainly not the most critical. Classical magnetic separation rack use **non-homogeneous magnetic separation**. When **scaling up production** on these devices, larger volumes can lead to longer and longer separation times.

This post is about biomagnetic separation with a **magnetic separation rack**, and how to scale-up this process. If you are interested in this topic, download our free ebook **The Basic Guide to Scale-up Biomagnetic Separation Processes**:

## Keeping separation time constant

The way to **keep separation times constant** in classical systems is by i**ncreasing the magnetic force** on the beads farthest from the magnets. But increasing the force on these distant beads will necessitate increasing the force by a great deal in the **retention zone**. Magnetic beads in the retention zone exposed to such great forces over time will **irreversibly aggregate**, causing a great deal of difficulty in the final separation.

It is very difficult to **balance time of separation and strength of magnetic force** so that you have a yield that is comparable to smaller production volumes.

In order to **easily move from one volume to another** in biomagnetic separation processes, it is imperative to have **well-defined conditions** for the separation. **Homogeneous biomagnetic separation systems** such as **SEPMAG** allow the magnetic force to remain constant throughout the entire volume of the device. If the magnetic force is well defined, it is **easy to scale up production** because the parameters do not need to be changed.

## Defining the ideal magnetic force

A well-defined magnetic force is a force that is **high enough for the beads to be magnetically saturated**, but low enough that **irreversibly aggregated beads do not form**. The force must also be high enough to **retain the beads during supernatant removal**. With the optimal magnetic forces known for various volumes, the only parameter that needs to be determined in the new volume is the **correct time of separation**. The separation time for larger systems can be estimated as:

t_{large volume}=t_{small volume}*(R_{large volume}*F_{large volume})/(R_{small volume}*F_{small volume})

where R is the **distance travelled by the farthest beads** and F the **magnetic force of the device**. The magnetic bead separation speed is **constant and is proportional to the magnetic force**. Therefore, the separation time is only dependent on the distance travelled by the beads to the retention area (usually the vessel radius).

Unlike classical systems, SEPMAG’s homogeneous magnetic separation systems can **easily monitor homogeneous magnetic bead separation conditions** by using built-in optical sensors, further simplifying the validation and quality control process. By making sure that all parameters are well-defined, scaling up using homogeneous systems becomes a much easier task **performed at a fraction of the cost**.

Don't forget to check these posts from our blog in order to get a deeper insight into the **scaling-up of biomagnetic separation processes**:

- Scaling Biomagnetic Separation Process avoiding irreversible aggregation problems
- Permanent magnets vs. Electromagnets: considerations for scaling up magnetic beads separation processes
- How to Avoid Safety issues when scaling up Biomagnetic Separation Process

Check www.sepmag.eu/resources to access to FREE eBooks on the subject, or contact us. We will be glad to help you to achieve an efficient magnetic bead separation process!