PNNL

Abstract

High-resolution ion mobility spectrometry-mass spectrometry (HR-IMS-MS) instruments have enormously advanced the ability to characterize complex biological mixtures. Unfortunately, HR-IMS and HR-MS measurements, and particularly their ultra-high resolution implementations, are typically performed independently due to mismatches in analysis time scales. Here we overcome this limitation by using a dual-gated ion injection approach to enable the analysis of complex mixtures using both ultrahigh-resolution IMS and ultrahigh-resolution MS platforms: a structures for lossless ion manipulations IMS (SLIM-IMS) platform, and a Q-Exactive HF Orbitrap HR-MS platform. The dual-gated ion injection approach allowed the new SLIM-Orbitrap platform to perform high-resolution ion mobility separations, high resolution mass analysis, and high-energy collision induced dissociation (HCD) simultaneously. The SLIM-Orbitrap was initially characterized using a mixture of standard phosphazene cations and demonstrated an average SLIM-IMS resolving power of ~254 while simultaneously obtaining ultrahigh mass measurement resolution and accuracy. SLIM-Orbitrap-HCD capabilities for combined HR-IM-MS/MS measurements for peptide identification are demonstrated, as well as its use for complex lipid mixture measurements where SLIM-IMS separations of lipids having identical masses and very similar structures are characterized. The SLIM-Orbitrap performance demonstrates a critical new capability for proteomics and lipidomics applications.