Following on from my earlier question on timings for US pre-clearance at Dublin airport, I've been watching the US pre-clearance at Dublin video from the Dublin airport website. That mentions that after checkin, passengers clear normal Irish security checks, then proceed (via optional shopping) to a TSA-style security check before reaching the CBP juxtaposed border control. It also mentions that duty free shopping is available after immigration and customs.
That leads me to wonder - can I buy duty free liquids in the main bit of Dublin Airport, before reaching the US pre-clearance area? Or must all duty free liquids (eg alcohol) be purchased in the smaller duty-free shop after US pre-clearance just before boarding?