I wonder if it is allowed by the regulatory agencies like FDA to use columns in reverse???
And if it is allowed does it need to be mentioned in the notebook?

Thanks for your kind help.

Why would you do that ?!

Are you talking about fliping the column? If so there is nothing wrong with it (unless manufacture recomends against). In fact it is recomended to prolong column life (It can correct small voids occasionally).

The FDA and USP have nothing to say about the direction of flow through the column. If you have a log book for the column, the flip should be mentioned there.

I meant if the column is flipped.

Sometimes the tailing factor fails with the regular flow direction of the column, flipping it improves the peak shape.

Thanks for the response everybody.

Dear Britney,

People typically flip the column for a type of "reverse flush" usually when something is clogged or when you want to clean the column. you can use the column in reverse but it's not recommended because most companies only test (QC) columns in one flow direction (these are for Reversed phase bonded type columns). I would personally suggest just a clean procedure instead.