GE HEALTHCARE Biacore T100, Handbook

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6 Evaluation software – general features
6.7 Solvent correction
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Biacore T100 Software Handbook BR-1006-48 Edition AE
A more detailed description of solvent correction background and procedures
may be obtained from GE Healthcare.
6.7.2 When solvent correction should be used
It is important to bear in mind that solvent correction is only relevant when
• the expected analyte responses are low (of the order of 50 RU or less),
• the ligand is a macromolecule immobilized at a high density (typically
5,000 RU or more – lower ligand densities lead to excluded volume effects
that are too small to merit correction),
• the bulk response is subject to variations between samples of at least the
same order of magnitude as the measured binding response.
Solvent correction should not be applied in situations that do not meet all three
of these criteria. Attempts to use solvent correction in other circumstances may
introduce errors that are larger than the solvent effects that the procedure is
intended to correct.
6.7.3 How solvent correction works
Solvent correction factors are determined by injecting a series of blank samples
containing a range of solvent concentrations over the active and reference
surfaces, and plotting the difference in relative response between the surfaces
as a function of the relative response on the reference surface. Each sample
measurement is then corrected by a factor obtained by measuring the relative
response on the reference surface and reading the corresponding difference
between active and reference surfaces from the correction curve (Figure 6-2).
Figure 6-2. The principle of solvent correction. 1 . The sensorgram from the reference flow
cell shows a bulk displacement (-150 RU in the illustration) during sample injection because
the sample and running buffer are not exactly matched.
2. From the solvent correction
curve, a displacement of –150 RU in the reference sensorgram corresponds to a solvent
error of +5 RU in the reference-subtracted sensorgram.
3. The reference-subtracted
sensorgram is corrected by subtracting the solvent error. This procedure is applied to every
point during sample injection.