Abstract: The invention provides a method of making a sample vessel comprising: (a) melting a plastics material (b) introducing the molten plastics material into a mold, and (c) allowing the plastics material to set in the mold; wherein the mold defines a cavity with the shape of a sample vessel which comprises a tubular portion, which tubular portion has a maximum external cross sectional width of up to 5 mm and an internal sample volume of up to 100 ?l wherein the tubular portion comprises a tubular external wall with a thickness of from 0.01 to 2 mm.