A designed experiments approach to optimization of automated data acquisition during characterization of bacteria with MALDI-TOF mass spectrometry

Lin Zhang, Connie M. Borror, Todd Sandrin

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

MALDI-TOF MS has been shown capable of rapidly and accurately characterizing bacteria. Highly reproducible spectra are required to ensure reliable characterization. Prior work has shown that spectra acquired manually can have higher reproducibility than those acquired automatically. For this reason, the objective of this study was to optimize automated data acquisition to yield spectra with reproducibility comparable to those acquired manually. Fractional factorial design was used to design experiments for robust optimization of settings, in which values of five parameters (peak selection mass range, signal to noise ratio (S:N), base peak intensity, minimum resolution and number of shots summed) commonly used to facilitate automated data acquisition were varied. Pseudomonas aeruginosa was used as a model bacterium in the designed experiments, and spectra were acquired using an intact cell sample preparation method. Optimum automated data acquisition settings (i.e., those settings yielding the highest reproducibility of replicate mass spectra) were obtained based on statistical analysis of spectra of P. aeruginosa. Finally, spectrum quality and reproducibility obtained from non-optimized and optimized automated data acquisition settings were compared for P. aeruginosa , as well as for two other bacteria, Klebsiella pneumoniae and Serratia marcescens. Results indicated that reproducibility increased from 90% to 97% (p-value≅0.002) for P. aeruginosa when more shots were summed and, interestingly, decreased from 95% to 92% (p-value ≅ 0.013) with increased threshold minimum resolution. With regard to spectrum quality, highly reproducible spectra were more likely to have high spectrum quality as measured by several quality metrics, except for base peak resolution. Interaction plots suggest that, in cases of low threshold minimum resolution, high reproducibility can be achieved with fewer shots. Optimization yielded more reproducible spectra than non-optimized settings for all three bacteria.

Original languageEnglish (US)
Article numbere92720
JournalPLoS One
Volume9
Issue number3
DOIs
StatePublished - Mar 24 2014

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matrix-assisted laser desorption-ionization mass spectrometry
Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry
reproducibility
Pseudomonas aeruginosa
Mass spectrometry
Data acquisition
Mass Spectrometry
Bacteria
bacteria
Experiments
Serratia marcescens
Klebsiella pneumoniae
Signal-To-Noise Ratio
Reproducibility of Results
Spectrum Analysis
Signal to noise ratio
Statistical methods
statistical analysis
experimental design
cells

ASJC Scopus subject areas

  • Medicine(all)
  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

A designed experiments approach to optimization of automated data acquisition during characterization of bacteria with MALDI-TOF mass spectrometry. / Zhang, Lin; Borror, Connie M.; Sandrin, Todd.

In: PLoS One, Vol. 9, No. 3, e92720, 24.03.2014.

Research output: Contribution to journalArticle

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