Enhanced Sensitivity in DESI Mass Spectrometry Imaging via a Dual‐Stage Ion Funnel: A Hybrid Simulation and Experimental Study

RATIONALE: While ambient mass spectrometry imaging (MSI) is essential for biological analysis, its sensitivity remains constrained by ion transmission losses due to collisions and gas dynamics. METHODS: Here, a high-performance desorption electrospray ionization (DESI) MSI system featuring a high-efficiency dual-stage ion funnel (DIF) was developed. To optimize the system configuration, a hybrid multiphysics simulation model was constructed by coupling gas dynamics, electric field, and ion transport simulations. RESULTS: The simulation model was validated against experimental data from mouse brain homogenates, confirming its accuracy in predicting ion transport behavior under realistic conditions. With the optimized DIF assembly, signal enhancements of up to 490-fold and the detection of 303 additional mass peaks in mouse brain sections were achieved compared to the standard S-lens interface. Furthermore, post-photoionization (PI) was introduced to expand molecular coverage to non-polar compounds and simultaneously enhance sensitivity. CONCLUSIONS: Overall, this study provides theoretical insights into ion motion within complex coupled fields and offers guidelines for the design of high-sensitivity ambient MSI interfaces.