Forum :: RU response to concentration

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This forum is intended for questions about kinetics, Surface Plasmon Resonance and the instruments related to these techniques.

TOPIC: RU response to concentration

RU response to concentration 13 Feb 2017 19:14 #1

How can we translate the RU response to the amount of ligand we would like to immobilize on our chip? In other words, how do we convert the RU response to concentration of ligand for injection?

Thank you.

RU response to concentration 13 Feb 2017 19:42 #2


First calculate the amount of ligand to be immobilized based on the relative size differences between ligand and analyte.

I assume you use the amine coupling on a dextran chip.
Then use a pre-concentration experiment to determine the correct pH and ligand concentration to get a pre-concentration rate between 15 – 40 RU/s. Use a report point during the pre-concentration to determine the slope in RU/s.

The actual ligand concentration is not of real importance as long as the pre-concentration is fast enough for the desired immobilization target. We use normally a maximum of 100 µl ligand solution (5 – 20 µg/ml) to immobilize between 200 – 5000 RU ligand (5000 – 160000 Da).

For more information and calculation please refer to

Kind regards

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