Optical Fiber-Coupled Flow Cells And Their Application In In-Situ Water Analysis

Liquid core wave guides (LCW) are particularly suited as flow-through cells for highly sensitive spectral analysis of small liquid sample volumes as the light propagation is constrained to the liquid core. We report on LCW formed by inside coating of glass capillaries with Teflon (R) AF 1600 (n approximate to 1.31). The wave guiding losses are between 0.2 and 0.3 dB/cm. On the base of fiber-coupled LCW flow-through cells both, a spectrophotometer and a fluorescence detector have been developed and tested for in-situ water analysis, especially for nitrate and phosphate detection in sea water.