SX20 Stopped-Flow Spectrometer

The gold standard for stopped-flow kinetics

The SX20 is the premier high performance stopped-flow spectrometer, built on over 20 years of innovative design and applications support.


  • Outstanding micro-volume performance; unsurpassed sensitivity
  • Follow rates in excess of 3000s-1 with sub-500μs dead-time
  • Optimised for all absorbance and fluorescence applications
  • Powerful, easy to use software for acquisition, display & analysis
  • World-class support and training to meet your future challenges


The SX20 is used to study transient and pre-steady-state kinetics of fast, liquid-phase chemical and biochemical reactions initiated by the rapid mixing and stopping (stopped-flow) of the reactants. A spectroscopic probe (absorbance or fluorescence) is employed to follow the course of the reaction by recording changes in the amplitude of the spectroscopic signal as a function of time. A typical upper limit to the reaction rates that can be measured with stopped-flow is ~2000s-1 in standard configuration; with smaller volume cells, rates in excess of 3000s-1 can be measured.


The wide range of applications for stopped-flow spectroscopy means there are many thousands of publications. The study of enzyme catalysis, protein refolding, signal transduction, ligand or drug binding to proteins or DNA and kinetics of coordination chemistry are numbered among the many applications of stopped-flow spectroscopy.


The SX20 is the undisputed market leader in stopped-flow. Applied Photophysics has supplied more than half of all the stopped-flow instruments in use today.

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SX20 Technical Datasheet

The British Assessment Bureau