Freeze Quench

The Freeze Quench accessory from Bio-Logic extends the SFM stopped-flow platform to quench-flow experiments, where the reaction is stopped not by a physical barrier but by rapidly freezing the mixed sample in a cold medium (-140°C isopentane), capturing transient intermediates for spectroscopic analysis.

Principle of operation:
– Reactants are mixed in the SFM mixer at defined time after mixing
– Mixed sample is sprayed into a rotating drum filled with cold isopentane (-140°C) or liquid nitrogen
– Frozen pellets are collected and packed into EPR tubes or Mössbauer holders
– Time resolution: 2-500 ms depending on flow tube length

Applications:
– EPR spectroscopy: characterize radical intermediates in enzyme reactions
– Mössbauer spectroscopy: monitor iron oxidation states in metalloproteins
– ENDOR/ESEEM: detailed hyperfine structure of paramagnetic intermediates
– Cryo-XAS: X-ray absorption of frozen intermediates at synchrotrons
– Frozen samples for cryo-EM analysis of transient complexes

Design:
– Compatible with SFM-2000, SFM-3000, SFM-4000 mixers
– Variable aging time via adjustable delay tube length (2-500 ms)
– Temperature of isopentane bath: -140°C (Freon or liquid N2 cooled)
– Collection yield: >90% of mixed sample recovered as pellets
– BioKine32 software controls mixing; quench is triggered mechanically

NewRoad provides Bio-Logic Freeze Quench accessory in Israel for spectroscopic characterization of enzyme and metalloprotein reaction intermediates.