Phase Modulation to Increase Ion Throughput for Ion Mobility-Time-of-Flight Experiments

Implementing a phase-based gating scheme with structures for lossless ion manipulation and a time-of-flight mass analyzer significantly enhances analytical efficiency. Phased ion mobility spectrometry substantially reduces the experimental analysis duration compared to single injection, signal-averaged structures for lossless ion manipulation (SLIM), without compromising separative capabilities. Notably, the observed duty cycle in phased ion mobility spectrometry increases 10x compared to signal-averaged SLIM experiments. A 6-m SLIM system, integrated with a time-of-flight mass analyzer, demonstrates equivalent separative capabilities and resolving power in both signal-averaged and phased-ion mobility modes. However, substantial duty cycle and ion efficiency improvements are evident during phased ion mobility spectrometry. The determination of the numerical integer required for accurate arrival times can be achieved algebraically or directly derived from measured arrival times in signal-averaged experiments. This methodology seamlessly integrates into existing single-gated SLIM or drift tube ion mobility-mass spectrometry instrumentation with minimal experimental adjustments, directly enhancing the observed duty cycle and reducing experimental analysis times.