Liquid AP‐UV‐MALDI Enables Stable Ion Yields of Multiply Charged Peptide and Protein Ions for Sensitive Analysis by Mass Spectrometry

Rainer Cramer,Franz Hillenkamp,Alexander Pirkl,Klaus Dreisewerd

doi:10.1002/anie.201208628

Rainer Cramer, Franz Hillenkamp + Show 2 more

Open Access

https://doi.org/10.1002/anie.201208628

Copy DOI

Abstract

All charged up: High and prolonged yields of multiply charged peptide and protein ions can be formed in MALDI mass spectrometry using liquid UV-MALDI matrices and a heated ion-transfer tube. The key features are low laser energies of 1–10 μJ, resulting in fluences of less than 200 to 2000 J m−2 and low sample ablation, high sensitivity, and continuous ion generation over tens of thousands of laser shots.

Highlights

In biological mass spectrometry (MS), two ionization techniques are predominantly employed for the analysis of larger biomolecules, such as polypeptides
Technique that can cover bioanalytical areas for which ESI is less suitable.[7,8]. If these strengths could be combined with the analytical power of multiply charged ions, new instrumental configurations and large-scale proteomic analyses based on MALDI MS(/MS) would become feasible
The absence of adduct ions for multiply charged ions is an important observation since liquid MALDI samples are typically a good source of salt cations and generally support cation adduct formation

Summary

Introduction

In biological mass spectrometry (MS), two ionization techniques are predominantly employed for the analysis of larger biomolecules, such as polypeptides. One of these employed electrospray deposition of at least 200 pmol of analyte on various preformed MALDI matrix layers, showing that under specific conditions highly charged insulin ions can be detected albeit at a low signal-to-noise ratio.[15]

Results

Conclusion