  We present chemical kinetics measurements of the luminol oxydation
chemiluminescence reaction at the interface between two aqueous solutions,
using liquid jet technology. Free-flowing iquid microjets are a relatively
recent development that has found its way into a growing number of applications
in spectroscopy and dynamics. A variant thereof, called flat-jet, is obtained
when two cylindrical jets of a liquid are crossed, leading to a chain of planar
leaf-shaped structures of the flowing liquid. We here show that in the first
leaf of this chain the fluids do not exhibit turbulent mixing, providing a
clean interface between the liquids from the impinging jets. We also show,
using the example of the luminol chemiluminescence reaction, how this setup can
be used to obtain kinetics information from friction-less flow and by
circumventing the requirement for rapid mixing but by intentionally suppressing
all turbulent mixing and instead relying on diffusion.
