Duty free Shop Suvarnabhumi airport upon arrival and depature

Just want to be sure that , once I arrived in Suvarnabhumi airport, can I walk pass by to the departure duty free shop and get some duty free stuff ? Does Bangkok airport have duty free? What can you buy at duty free shops in Suvarnabhumi airport? is it possible to get to duty-free shopping area of the Suvarnabhumi airport after landing?