Flow cell with an inner layer of an amorphous fluoropolymer having a refractive index less than the refractive index of water

摘要

A flow cell (10) for optically analyzing a liquid sample is coated with an amorphous fluoropolymer (12) (eq. Teflon AF) having a refractive index less than the refractive index of water. The cell (10) has a fluid input section (14) connected to the exit (16) of a capillary liquid chromatography or capillary electrophoresis separation column, and a fluid outlet section (18). Light from light source (20) enters input optical fiber (22) and is directly axially into the bore (24) of cell (10) through which sample stream (26) flows. The light is guided by total internal reflection at the boundary between liquid (26) and layer (12) and leaves the cell through exit optical fiber (28) to be measured by detector (30). Cell body (32) provides mechanical strength and seals for fluid connections (14 and 18) and optical fibers (22 and 28).