protein isocratic HPLC.. preparatin of tris buffer + n-propanol mix - getting variations in Retention time.. (Sep/10/2008 )

hi all.. my protein isocratic HPLC.. involves a preparatin of tris buffer + n-propanol mix as a mobile phase.. due to variations in buffer preparation.. i m getting variations in Retention time..

how does one make such a buffer mix??
i have done volume measurement in a measuring cylinder calibrated well..

let me know!!

thanks!

are you talking about run-to-run, day-to-day, or mobile phase batch-to-batch variation?

each of these may have different (albeit possibly similar) reasons.