Measurements of
absorbance at 565 nm were carried out with a spectrophotometer
(USB 4000 UV–vis, Ocean Optics) coupled via optical fibers (600 μm diameter) to aliquid waveguide capillarycell (LWCC,
World Precision Instruments) with a flow path of 100 cm (inner
volume 250 μL) and to a light source (Model LS-1-LL halogenlamp,
Ocean Optics).