Instrumental Dispersion Evaluation on Supercritical Fluid Chromatography-Medium Vacuum Chemical Ionization Tandem Mass Spectrometry

Le résumé fourni par la source

Instrumental dispersion in the ion source can severely distort fast chromatographic peaks in supercri cal fluid chromatography (SFC)-mass spectrometry (MS).Despite this importance, the dispersion characteris cs specific to medium-vacuum chemical ioniza on (MVCI) sources have not been quan ta vely inves gated.In this work, we combine targeted experiments with established computa onal toolscomputa onal fluid dynamics (CFD) and electrosta c field simula on-to characterize ion transport in the MVCI flow tube.Arrival profiles of vitamin K1 (VK1) ions monitored by selected ion monitoring consistently showed a reproducible two-component structure consis ng of an early narrow bandwidth ion packet followed by a delayed shoulder.CFD calcula ons reproduce this tailing peak profile, and electrosta c modeling further revealed that applying the same poten al to the MVCI flow tube and inner cylinder generates lateral poten al walls that inhibit long-residence-me ions from entering the skimmer.Introducing an appropriate poten al difference between the MVCI inner cylinder and the skimmer orifice isolates the MVCI flow field from the ion guide region and suppresses long residence-me trajectories, which narrows the VK1 peak width by more than threefold and restores the intrinsic column efficiency of a sub-2-µm SFC column (from the theore cal plate (N)=3120 to 12079).

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