High Pressure Stopped-Flow System
Product code: HPSF-56
The HPSF-56 high pressure stopped-flow system is derived from an original design by Prof. André Merbach at the University of Lausanne, Switzerland. Featuring both UV/Vis and fluorescence measurement capabilities, the system has an empirical dead time of less than 10 ms and allows stopped-flow determinations to be made at pressures up to 2000 bar. 
A modular approach to instrument construction makes it easy to use. The chemically inert flow circuit and observation cell with 3 sapphire observation windows are arranged as a sub-assembly within a thermostatted high pressure vessel. The sample handling system is mounted on a frame that carries associated support equipment and can be loaded with sufficient reagent for 25-30 experiments. The pneumatic press is mounted on a track to allow it to be moved aside whilst loading the pressure vessel.
System pressure is generated by a pressure intensifier with a hand pump for small adjustments to ensure accuracy. Continuous and accurate monitoring of pressure is achieved using a transducer and digital display. Comprehensive safety interlocks protect both the system and operator.
Direct coupling of the optical system to the sapphire windows which in turn are in direct contact with the reactant mixture ensures optimum sensitivity and accuracy. The pressure vessel has an integral thermostatted jacket and a temperature monitor is provided.
An adjustable incremental sample drive system ensures accurate mixing of solutions is achieved in milliseconds and data acquisition is facilitated through the provision of a selectable transition trigger output.
Probing isotope effects in enzyme catalysis using High Pressure Stopped-Flow
In recent work1 an HPSF-56 high pressure stopped-flow system equipped with a KinetaScan diode array system has been used at the Manchester Interdiciplinary Biocentre, UK by Professor Nigel Scutton and co-workers to study the pressure dependence of kinetic isotope effects, coupled with a study of their temperature dependence, as a probe for promoting motions in enzymatic hydrogen-tunneling reactions. Employing morphinone reductase as a model system they have measured the hydride transfer rate (a tunneling reaction) as a function of hydrostatic pressure and temperature. Increasing the pressure from 1 bar to 2 kbar was found to accelerate the hydride transfer reaction when both protium and deuterium are transferred.
1. Sam Hay, Michael J. Sutcliffe, and Nigel S. Scrutton (2007), PNAS, 104, No. 2, 507-512
