Instrumentation Laboratory Project Page
Project: Freeze Quench System
Department: Chemistry and Biochemistry
Primary Investigator: Dr. David Tierney
Purpose: The freeze-quench apparatus was built to be able to stop chemical reactions on very short timescales (< 1 ms). Reactants are mixed externally and sprayed onto the counter-rotating copper wheels, which are kept at 77 K, freezing the reaction mixture on contact. The counter-rotating wheels allow us to easily vary the mixing time prior to freezing, and ensures instantaneous and uniform freezing. It is primarily used for the study of enzymatic reactions, with the purpose of stopping the reaction at various times, and then studying the frozen reaction mixture using spectroscopy. Samples for spectroscopy are collected beneath the wheels in a funnel immersed in liquid nitrogen, and the funnels are easily modified to mount different sample holders.
IL Comment: The biggest challenge in designing
this system was designing it so that the secondary wheel kept tension
against the drive wheel, but at the same time could move as there was
ice/sample buildup on the two wheels. Also designing the "scrappers"
setup so to keep the wheels clean and to catch the frozen sample before
it went between the wheels again. Also, after seeing the examples
provided by the user, added a bushing between the motor and the drive
wheel to reduce noise and vibration.
Cost to researcher: $474.38