Enhancing data acquisition for the analysis of complex organic matter in direct-infusion Orbitrap mass spectrometry using micro-scans

Rationale Acquisition quality in analytical science is key to obtaining optimal data from a sample. In very high-resolution mass spectrometry, quality is driven by the optimization of multiple parameters, including the use of scans and micro-scans (or transients) for performing a Fourier transformation. Methods Thirty-nine mass spectra of a single synthesized complex sample were acquired using various numbers of scans and micro-scans determined through a simple experimental design. An electrospray ionization source coupled with an LTQ Orbitrap XL (TM) mass spectrometer was used, and acquisition was performed using a single mass range. All the resulting spectra were treated in the same way to enable comparisons of assigned stoichiometric formulae between acquisitions. Results Converting the number of scans into micro-scans enhances signal quality by lowering noise and reducing artifacts. This modification also increases the number of attributed stoichiometric formulae for an equivalent acquisition time, giving access to a larger molecular diversity for the analyzed complex sample. Conclusions For complex samples, the use of long acquisition times leads to optimal data quality, and the use of micro-scans instead of scans-only maximizes the number of attributed stoichiometric formulae.