Structural Insights of Human Centrin 2

55th ASMS Conference – Indianapolis 2007 www.chemistry.wustl.edu/~msf/ Overview Purposes •Evaluate the resolving power and sensitivity achievable with a new compensated trap for FTMS as a function of m/z and develop a protocol for tuning this trap. Methods •Sample empirically the cyclotron frequency surface at various cyclotron radii and z-mode amplitude distributions. •Compare the mass resolving power and sensitivity at various m/z’s achievable with a compensated trap compared to those achievable with the conventional (uncompensated) trap. Results •Compensated trap achieves nearly three fold increase in apparent resolving power and a ten fold increase in sensitivity. •An experiment-based algorithm flattens the frequency surface of the new trap in one step. •The flattened surface, achieved by applying voltages to auxiliary rings, insures a more constant ion frequency as a function of ion mode amplitudes, than does uncompensated trap.