Hi everyone,
Each time I try to filter multiple parallel samples with Amicon Ultra centrifugation filters (@MerckMillipore), one or more of those filters seems to filter slower than the others. At the end, the fitrate volume varies significantly among samples (from the same centrifugation run). This happens even when samples contain the same ingredients at the same concentration. It is quite tedious to equilibrate the passed volume for all samples if you have several washing steps.
Could you please suggest why is the reason and what can be done to avoid such condition?