Originally Posted by SK AAR

Arriving from the US should allow you to proceed straight to the departures level bypassing the main transfer security checks. There is no passport control but TK staff will check you onward BP.

Just ask staff at IAD store to put the bottles in a sealed transparent plastic bag (the receipt should be in the bag and visible from outside); staff should know about this. Then you would be able to take it through transfer security checks with no issue.