Modification of Bradford Assay with SDS - THe attempt to increase sensitivity for a protein with SDS (Dec/10/2009 )

Hey,

So i was running a bradford assay with BSA, and coomassie plus dye, and the standard curve looks great. I then tried to run a unknown sample and also a standard dilution with collagen stock solution, and obtained a 4 fold lower curve. So low that my unknowns dont even appear. I was trying to increase sensitivity by using SDS. Most references say to use about .0035%. From my understanding that is .0035=X(g)/100ml correct? which is about .35g SDS added to each sample of 100ml. Is this the correct way to go about this? I did this and all my samples were way blue, and I got no curve at all. It was essentially a straight line.

.0035% = .000035, so you have 100x times too much SDS.