SDS electrod buffer - SDS electrod buffer (Dec/08/2004 )

Hi,
have troubles with pH of SDS electrod buffer (10x stock). Use 25O mM Tris, 1,92 M glycine, 0,1% SDS, pH 8,3. Now, made new stock, but didn´t work... I measured pH and it was 10,5 and caused that SDS doesn´t work how it should... and, there is written in protocol, don ´t adjust pH, it´s 8,3...I also changed mark of chemicals but it´s the same...What happen if I adjust pH (by HCl e. g.)? Do I influence the protein in sample-or????
Can anybody help me?
Thanx a lot! Lenca

Hi,

I use nearly the same buffer for SDS-PAGE and it works well. But my stock solution is only 5x and I don't adjust the pH. If the protocol says you shouldn't adjust the pH then don't do it!
The pH changes when you dilute the buffer. But maybe it works when you use a 5 x buffer.

Good luck,
Juillet

My stock is 10x and I don't check pH in concetrated buffer but when I dilute it to 1x I always measure pH and is between 8.3 and 8.5. Measure pH of water (between 5-6) you are going to use and assure you add the correct concentrations of the salts. I don't know why this buffer cannot be adjusted but maybe Cl ions could affect with electrophoresis or with the proteins.