Teflon AF-2400 capillary (i.d. 0.29 mm, o.d. 0.5 mm) was used as a liquid core waveguide cell with an aqueous solution sample. The refractive index of the Teflon AF-2400 capillary (n=1.29 (632.8nm)) is lower than that of water (nD=1.33), thus, the capillary formed a liquid core waveguide and was elongated up to 117 cm long. The sensitivity in detecting methylene blue with the 30 cm capillary cell was enhanced about 32-fold in comparison with that of a conventional cell (1cm). The cell (30cm) was applied to the spectrophotometric determination of sulfur in a standard steel sample after distillation of sulfur as hydrogen sulfide.
