A Method for Monitoring and Controlling Reproducibility of Intensity Data in Complex Electrospray Mass Spectra: A Thermometer Ion-based Strategy

Reproducibility in mass spectral data is important in both biomarker discovery and spectral database searching. We report a strategy, employing a series of substituted benzylpyridinium thermometer ions that can be used to monitor changes in performance of multiple aspects of an electrospray ionization source that impact the intensity axis of a spectrum. Performance attributes, which could confound even isotope-based quantification strategies, are readily assessed using a mixture of thermometer ions. Based on the observed behavior of the ions, a procedure is proposed for monitoring instrument performance and compensating for factors that affect reproducibility across both time and instruments.

Graphical AbstractCharacterization and control of reproducibility in ESI spectra using the fragmentation behavior of thermometer ion mixtures under a variety of source conditions.Figure optionsDownload full-size imageDownload high-quality image (275 K)Download as PowerPoint slide