Quenstion about Solvent correction

I have to measure the Kinetic/Affinity (using Biacore T200) of small molecule drugs which has to dissolve in 1% DMSO. According to the GE protocol , I have to do the solvent correction in the assay. So I got the question, Why can't I just add the 1%DMSO in the running buffer(PBS+0.05%P20) to avoding the bulk affect of buffer changing.

Thank you

Adding 1% DMSO to the running buffer is a good idea. However, even small (<0.1%) differences in DMSO concentration between running buffer and analyte can give large bulk effects. Even when you add the 1% DMSO to the running buffer I would recommend to add the solvent correction.
Second option is to 'titrate' the DMSO concentration in the running buffer until it matches the analyte concentration but this can be a lot of work.

Arnoud