Hi everyone,

I have a question that has been troubling the whole lab here with the SDS-PAGE gel staining. We usually use colloidal gel staining (ROTI blue quick) and it works fine every time. Intensive blue bands which we can see clearly.

However recently we change to a different stain (namely the Imperial Protein Stain from Thermo Fischer Scientific). Now this stain doesn't really work nicely. Instead of staining the bands, it made the gel look purplish instead. After destaining several times, we can see the bands but not as intense.

I have searching for reasons why this could be but could not really find anything. Does anyone have any idea why? Or what we can do to utilize this stain? (as we have like 3 bottles but as of now not used since it didn't work).

This happens to all of the protein samples we are working on in the group.

The concentration of each sample: 6 microgram/mL. We put 10 microliter in each well.

If anyone can be of any help, is highly appreciated!