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Product Overview
SFM-2000, SFM-3000,

SFM-4000 Stopped-flow

A versatile stopped-flow mixing system designed to offer extreme precision as well as minimize the consumption of often expensive samples.

A range of single, double or triple stopped-flow mixing systems designed to ensure the shortest possible dead time.


The stopped-flow mixing system offering accuracy, precision, and versatility.

A stopped-flow mixing system is an essential instrument for rapid kinetics investigations. A complete stopped-flow instrument is a mixing device coupled to a detection system. Two, three or four sample solutions are rapidly mixed and injected into an observation cell. When the flow is stopped, the kinetics are recorded with a detector chosen according to the chemical properties of the solutions and the information of interest (e.g. particle size, the environment of fluorophore, chromophore).

The SFM-4000 stopped-flow series is available for single, double or triple mixing applications (two reaction steps or one reaction step and one concentration change step before the final observed reaction). The SFM-4000 stopped-flow family has been designed to ensure the shortest possible dead time the highest precision and to minimize sample consumption as much as possible.

Applications include protein folding/refolding, protein-protein interactions, fluorescence resonance energy transfer (FRET), ligand binding, water and ion transport in vesicles and membranes, enzyme/substrate reactions, coordination reactions in inorganic chemistry, as well as identification or capture of intermediates, and more. Virtually any application with a timescale in the range of 0.5 ms. to minutes is observable by our stopped-flow systems. The same stopped-flow mixers can be used with chemical quench or freeze quench accessories to collect time point samples for EPR, NMR, Mossbauer, or GC/MS analysis when the reaction has no appropriate optical signature.


Free mixing ratio change.

Mixing ratios can be freely changed by the user because our stopped-flow mixers use independent stepping motor technology. This technology provides microliter precision and accuracy at all flow rates, over a wide viscosity, temperature, and mixing ratio range. The user has a full control of volume, speed and mixing ratio from within Biokine software. A series of shots at various concentration can be programmed and run quickly without refilling or changing syringes. Advanced Berger-Ball technology mixers are used to provide the best turbulent mixing over the widest range of flow conditions.

Short dead time.

With our SFM series technology, it is possible to achieve sub-microsecond dead times for following kinetics with a rate constant up to 3500 s-1. The standard dead time reachable by our SFM-4000 family systems is 700 µs, and 200µs is possible using the optional microcuvette for the most demanding applications. This extremely low dead time is achievable thanks to the precision drive mechanism and the quality of the stop mechanism. Quench flow and freeze quench applications have minimum ageing times of 2 ms.

Stopped-flow Modularity.

The stopped-flow is easily adaptable to a wide variety of rapid mixing techniques and applications. The unique design is based on open access to the mixing chamber and the use of independent stepping motor technology. Therefore, the stopped-flow system can be switched from optical stopped-flow to chemical quench-flow, to freeze quench, to cryo stopped-flow to a beamline, to laboratory designed optical benches, all in minutes, with off the shelf options. A range of off-the-shelf accessories enables you to adapt the SFM-series to your specific needs in the lab, without buying a complete new system. Additionally, our R&D team provides special development services to customize the stopped-flow system and produce bespoke systems to meet your specific needs and applications.

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