Inter-platform assessment of performance of high-throughput desorption electrospray ionization mass spectrometry

Abstract

High throughput analysis is increasingly relevant in both industry and academia, with applications reaching from enzymology and drug discovery to organic reaction optimization and diagnostics. Currently, chromatography-free mass spectrometry (MS) techniques have acquired an important role in this field due to their inherent speed, versatility, and chemical specificity. Desorption electrospray ionization (DESI) MS is one of these approaches, which allows for direct analysis of complex samples in the ambient environment, with throughputs better than 1 sample per second and no need for sample treatment. Here we assess the evolution of the high throughput DESI-MS analytical performance from the early DESI source developed by Prosolia Inc. to the recently commercialized version of Waters Corporation. The evaluation was carried out through both quantitative and qualitative analysis of biologically relevant compounds including metabolites, peptides, lipids and pharmaceuticals. Our results indicate that both platforms are successful at the direct analysis of these species even from complex matrices such as bioassay buffers. However, the newest iteration of the DESI stage, when combined with a quadrupole time-of-flight (Q-ToF) instrument, provides higher sensitivity (1-3 orders of magnitude lower limits of detection) and reproducibility (ca. 10% average reduction in coefficients of variation for quantitation using an internal standard). The cases explored in this study also showcase the broad applicability of high throughput DESI-MS for bioanalysis and quality control.

Keywords

• analytical performance
• ambient ionization
• steroid sulfates
• opioid peptides
• lipids
• compound library