Graphite Furnace for AAVersión en línea Label the parts of a graphite furnace for atomic spectroscopy. por Heather Holmes 1 Inert gas is sent through these openings to flow over the tube and protect it from oxidation. 2 Liquid sample is introduced here. A micropipette or autosampler is usually used. 3 This is the outer tube that contains the furnace. 4 This is the sample platform within the furnace. 5 Source light enters the furnace here. 6 Optical Window 7 This shows the graphite tube within the outer casing.