A sample presentation device for radiation-based analytical equipment comprising a mounting base, a carrier carried by, and adjustable in position, relative to the mounting base, and an arm extending from the carrier and having at its opposite end a terminal member; Each of the carrier and terminal member has a coaxial connector for receiving two opposite end regions of a capillary tube that forms, in use, a reaction cell; A radiant heater, typically an infrared heater, is radially offset from the axis of the coaxial connectors for heating, in use, a capillary tube mounted by way of the coaxial connectors; The carrier and terminal member preferably have heaters associated therewith for heating the flow passages through them; The terminal member preferably has a passage generally coaxial with the connector for receiving a communications conductor carrying a temperature sensor at its end that is operatively located generally centrally within a capillary.