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In a standard magnetic separation rack, scaling up to a larger lot volume usually creates four common problems:

1. Larger batches do not have the same characteristics as smaller lots.
2. The percentage loss of magnetic beads and biomolecules increases.
3. Irreversible aggregation becomes a serious issue.
4. Different aliquots (i.e. single IVD kits) of the same batch in large volumes have very different characteristics.

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:

## The root of all problems

These problems are common in classical magnetic separation racks because these devices do not generate homogeneous magnetic forces. In classical systems the force on the bead varies with the distance from the magnet. Beads far from the magnet experience very low forces and beads in the retention area experience high, sometimes excessive, forces.

Because the forces the beads experience are not constant, the characteristics of beads in larger batches will vary depending on where in the container they were at the start of the separation process. In addition, lot-to-lot variation is common because forces between lots of different volumes are not consistent.

Irreversible aggregation increases in classical magnetic separation racks, and it can be solved with techniques such as the sonication method. It takes either longer separation times or higher forces to move distant beads to the retention area. Beads that are exposed to higher forces over longer periods of time are highly susceptible to irreversible aggregation. If you choose not to increase force in order to avoid problems with the beads near the magnet, you will suffer a decrease in magnetic bead yield.

## How advanced systems solve these problems

Homogeneous systems such as SEPMAG maintain constant force on the beads no matter where the beads are in the container. Since the force is constant, the above limitations disappear. If the value of the magnetic force is chosen wisely, you can capture the beads lying far from the magnets while maintaining a gentle force in the retention area, thereby eliminating material losses and irreversible aggregation.

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: