Abstract: A light-pipe flow cell (10) for high pressure fluids is disclosed which has a main support body (15) with a gold light-pipe element (22) mounted therein. Infrared transmissive windows (26, 27) are mounted to the main support body against sealing rings (31, 32) to seal off the polished central bore (23) of the light-pipe element from ambient atmosphere while allowing an infrared beam to be passed therethrough. Pressure plates (14, 18) are mounted to the main support body (15) to apply pressure to the windows over the sealing rings to tightly seal the windows without exerting undue stress thereon. Flow of liquid or supercritical fluid from a chromatography column is directed through inlet channels (35, 38) in the support body and light-pipe element to one end of the light-pipe bore (23) and out of the opposite end of the bore through a channel (41) in the light-pipe element and a communicating channel (36) in the main support body.