New desorption strategies for the mass spectrometric analysis of macromolecules

TLDR

The authors introduce two novel desorption strategies—surface‑enhanced neat desorption (SEND) and surface‑enhanced affinity capture (SEAC)—to enable protein discovery and macromolecular structure analysis directly on chemically defined probe surfaces. These strategies rely on probe surfaces engineered with defined energy‑absorbing molecules: SEND surfaces enhance desorption of intact macromolecules presented alone, while SEAC surfaces capture specific macromolecules from unfractionated biological fluids for subsequent analysis. Laser‑assisted SEND and SEAC time‑of‑flight mass spectrometry examples demonstrate improved selectivity, detection sensitivity, and mass accuracy.

Abstract

Abstract We present two new desorption strategies for the mass spectrometric analysis of macromolecules. These desorption strategies are based on the molecular design and construction of two general classes of sample ‘probe’ surfaces. The first class of surfaces is designed to enhance the desorption of intact macromolecules presented alone (neat) to the surface; we call this surface‐enhanced neat desorption (SEND). The availability of probe surfaces derivatized with, or composed of, multiple types and defined numbers of energy‐absorbing molecules will facilitate investigations of energy transfer and desorption/ionization mechanisms. The second class of probe surfaces is designed to enhance the desorption of specific macromolecules captured directly from unfractionated biological fluids and extracts; we call this surface‐enhanced affinity capture (SEAC). Use of these new probe surfaces as chemically defined solid‐phase reaction centers will facilitate protein discovery through molecular recognition in situ , and also macromolecular structure analysis through the sequential chemical and/or enzymatic modification of the adsorbed analyte in situ . Specific examples of laser‐assisted SEND and SEAC time‐of‐flight mass spectrometry are presented to illustrate the potential for increased selectivity, analyte detection sensitivity, and mass measurement accuracy.