Building on SLIMPHONY, which is our traveling-wave SLIM instrument, CLOCK is a quantitative framework for probing the conformational dynamics of gas-phase protein ions. Its key advantage over conventional collision-induced unfolding is that it controls the magnitude of activation (via the guard electrode potential) and its duration independently, giving access to time scales from below a millisecond to seconds. By combining CLOCK experiments with ion trajectory simulations and statistical modeling, we translate instrument conditions into effective translational temperatures, ranging from roughly 350 to 600 K, and use it to compare activation conditions on common footing.
Conformational Landscapes Observed through Controlled Kinetics (CLOCK): Precise Control of Ion Temperatures from Sub-Millisecond to Second Time Scales. AnneClaire Wageman, Yuan Feng, Addison E. Roush, Rilke L. K. Grimlund, Matthew F. Bush. J. Am. Soc. Mass Spectrom. 2026, 37, DOI: 10.1021/jasms.6c00218. (Link)
A Python library for estimating effective translational temperatures, along with representative data and interactive notebooks, is available on our Github site.