how to validate the transfer condition (time/V or mA) for proteins of different molecular weight in western blotting?what could be the best transfer condition for proteins 14-30 KDa and 30-100KDa?
To validate protein transfer, you can use Ponceau S staining after transfer. That is usually quick and easy. The transfer conditions depend a bit on the system you are using. I use the biorad transfer chambers and transfer at constant Ampere (0.15 A for 2.5 hours). That usually works fine for the size of proteins between 10 and 150 kDa. If you think that you are loosing your smaller sized proteins, you always can put a second membrane behind the first to catch them before they are lost in the blotting paper.