Improve ICP-OES plasma torch lifespan by switching to a ceramic D-torch. Replacement Thermo Scientific™ Outer Tubes for Thermo Scientific ICP-OES Ceramic D-Torches are made from a durable, ceramic material derived from silicon nitride, which is resistant to chemical degradation. These properties are maintained at high temperatures and help prevent the potential devitrification associated with traditional quartz torches. When needed, quartz replacement outer tubes are also available for the D-Torch.