Document 4400Q902 version 1.02
Page 9 of 18
RX2000 User Manual
1 INTRODUCTION
Figure 1.1: the RX2000
The RX2000, shown in Figure
, is a high performance stopped-flow unit that enables your existing UV-visible
spectrometer, fluorimeter or circular dichroism (CD) spectrometer to be used to follow reactions that are at least
a thousand times faster than those accessible manually. With a dead-time of only 8 ms, first order reactions with
rates in excess of 200 s
-1
can be followed.
The RX2000 is easily the most accomplished device of its type, making use of the latest advances in stopped-
flow design, combined with the simplicity, robustness and reliability of high quality instrument engineering. In one
action the RX2000 mixes two reactants, fills a sample cell, stops the flow and simultaneously provides an output
trigger. Its dual pathlength micro-volume cell employs the latest silica fusion technology to give the highest
possible optical efficiency and specification. All crucial sample flow circuit surfaces are biocompatible and
chemically inert. In addition, carefully selected materials are used throughout to protect the instrument from
aggressive chemicals. The entire flow circuit and the drive syringes themselves are located within a
thermostatable bath for accurate sample temperature control.
The stopped-flow technique for the rapid mixing of chemical reagents has gained widespread acceptance as
being a most useful and versatile method for obtaining reaction rate information. After the two reagents are
mixed, the course of their reaction together can be followed in conjunction with single beam UV-visible
absorption or fluorescence spectrometry as appropriate, using the optical absorption or emission properties of
either the initial reagents, or a product or a reaction intermediate. Changes in light scattering within the reaction
cell provide another measurement method. The technique finds applications in chemistry (redox reactions, metal-
ligand complexes, solvation, dye binding etc.), biochemistry (enzyme kinetics, electron and proton reactions,
binding of poisons to biologically important molecules, calcium and sodium ion interactions, protein binding,
enzyme conformation and denaturation studies) and biophysics (cell membrane studies, osmotic swelling,
oxygen uptake and release by red blood cells).
This User Manual gives comprehensive information about how to configure and operate the RX2000 Rapid
Mixing Stopped-Flow Unit.