Universiteit Utrecht has the intent to acquire two Bruker timsTOF Ultra mass spectrometers for the Biomolecular Mass Spectrometry and Proteomics group of prof. dr. Albert J.R. Heck and dr. Nicola Ternette of its Faculty of Science. Universiteit Utrecht has the intent to require new mass spectrometers for the Biomolecular Mass Spectrometry and Proteomics group of prof. dr. Albert J.R. Heck and dr. Nicola Ternette of its Faculty of Science. The mass spectrometers need to be ultra-sensitive mass spectrometers, with 2-dimentional peptide separation capabilities that will be used for proteomics research to address diverse and challenging biological questions, including (but not necessarily limited to): • Protein complex analysis, including determining collisional cross section • Post-Translational-Modifications, e.g. phosphorylation, glycosylation • Analysis of low-abundant cellular sub-peptidomes, i.e. HLA peptides • Capacity for highly reproducible 2-dimensional peptide separation for high resolution sequencing of complex peptide mixtures without prior fractionation • Capability to separate and select different molecule ion charge states efficiently • Highly reproducible ion mobility separation for accurate prediction of Collisional Cross Section (CCS) for integration into ML-based spectral interpretation tools to assist de novo sequencing analysis