MS <i>SIEVE</i>–Pushing the Limits\nfor Biomolecular Mass Spectrometry

Electrospray mass spectrometry has become indispensable\nin many\ndisciplines including the classic “omics” techniques\nsuch as proteomics or lipidomics, as well as other life science applications\nin molecular, cellular, and structural biology. However, a limiting\nfactor that often arises for the detection of biomolecular analytes\nis their poor ionization efficiency in the ion source. Here, we present\nan add-on device for the electrospray source, termed MS <i>SIEVE</i> (MS Spectral Impurity Eliminator & Value Enhancer), which is\nplaced between the electrospray needle and the cone of the mass spectrometer.\nWe probed the application of MS <i>SIEVE</i> for various\nbiomolecules including proteins, peptides, lipids, glycans and DNA\noligonucleotides and even synthetic polymers such as polyethylene\nglycol and found that MS <i>SIEVE</i> selectively improves\nthe signal intensity, while suppressing the spectral contribution\nof contaminants such as NaCl. Importantly, MS <i>SIEVE</i> can, in principle, be adapted for any electrospray ion source and,\ntherefore, represents a promising alternative for routine “omics”\nmethods as well as special applications on challenging analytes.