Hydrogen exchange reactions millisecond

In a standard hydrogen exchange experiment (see Section 2.3.4 for variations in experimental workflow), the sample is deuterated for a predetermined time (milliseconds and longer times), and the reaction is slowed down several orders of magnitude by the addition of an acidic quench solution. Quenched reactions can be subjected to direct mass spectrometry analysis or immediately flash frozen in liquid nitrogen and stored at -80°C in multiple aliquots for future analysis. These flash-frozen samples need to be thawed prior to mass spectrometry. It is important to note that freeze-thaw cycles contribute to signal loss due to back-exchange (this is described further in Section 2.3.8), which... 

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