How do I detect when the column is compromised and needs cleaning?

If the column is compromised, you may observe some (or all) of the following:

• The flow rate begins to slow when compared to the original flow rate. It is recommended to measure the rate for the initial flush (and/or buffer volume). The column either needs to be washed or replaced when the flow rate has been increased by 25% of the original flow rate.

• If the recovery rate drops significantly over previous samples that are of similar origin (and therefore expected yield of EVs).

• A colour change is observed at the top of the column after flushing.