Interferences and contaminants encountered in modern mass spectrometry

Keller, Bernd O.; Sui, Jie; Young, Alyson L.; Whittal, Randy M.

doi:10.1016/j.aca.2008.04.043

Cited by 548 publications

(487 citation statements)

References 79 publications

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“…It is hardly feasible to transmit ions below 100 Da efficiently into the ICR cell by tuning instrument parameters. Some peaks with higher m/z values differ by 44.0263 Da, which corresponds to C 2 H 4 O, indicating that these peaks may represent polyethylene glycol (with an increasing number of monomers) which is a common contaminant in ESI 37,38 . Different Kendrick plots were obtained from ESI and APCI experiments (Figure 1) since different species tend to ionize with these techniques, and these results will be discussed in detail below.…”

Section: Resultsmentioning

confidence: 99%

Investigating the Trace Polar Species Present in Diesel Using High-Resolution Mass Spectrometry and Selective Ionization Techniques

et al. 2015

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The trace polar species present in diesel were investigated by combining selective ionization with high resolution mass spectrometry. To eliminate matrix effects, the polar fraction was extracted using methanol and direct infusion with electrospray ionization and mass analysis were performed. The advantages and limitations of time-of-flight mass spectrometry and Fourier transform ion cyclotron resonance mass spectrometry for diesel analysis were discussed.Complementary information was obtained by considering both positive and negative ion mass spectra in terms of compounds that form part of the inherent fuel composition and compounds that represent fuel additives. Additionally, diluted fuels were separated by gas chromatography prior to atmospheric pressure chemical ionization and mass analysis. Results showed that a large portion of unsaturated polycyclic hydrocarbons were not detected during direct infusion experiments, indicating that these species were not extracted efficiently with methanol and/or ionized efficiently with electrospray.

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Section: Resultsmentioning

confidence: 99%

Investigating the Trace Polar Species Present in Diesel Using High-Resolution Mass Spectrometry and Selective Ionization Techniques

et al. 2015

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“…External calibration was performed based on monoisotopic values of well-defined peptides. Obtained mass spectra were corrected for matrix-and enzymederived interferences (Keller et al, 2008). The resulting monoisotopic list of m/z values was submitted to the search engine MASCOT (Perkins et al, 1999) searching all proteins and DNA sequence information from public databases (MSDB, Swiss-Prot, NCBInr) and the translated partial genome sequence information from Parachlamydia acanthamoebae UV7 and Acanthamoeba castellanii containing 2931 Parachlamydia sequences and 12 990 sequences of Acanthamoeba.…”

Section: Mass Spectrometrymentioning

confidence: 99%

Proteomic aspects of Parachlamydia acanthamoebae infection in Acanthamoeba spp.

et al. 2010

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The free-living but facultatively pathogenic amoebae of the genus Acanthamoeba are frequently infected with bacterial endosymbionts that can have a profound influence on the physiology and viability of their host. Parachlamydia acanthamoebae, a chlamydial endosymbiont in acanthamoebae, is known to be either symbiotic or lytic to its host, depending on the ambient conditions, for example, temperature. Moreover, parachlamydiae can also inhibit the encystment process in Acanthamoeba, an essential survival strategy of their host for the evasion of chemotherapeutic agents, heat, desiccation and radiation. To obtain a more detailed picture of the intracellular interactions of parachlamydiae and acanthamoebae, we studied parachlamydial infection in several Acanthamoeba isolates at the proteomic level by means of two-dimensional gel electrophoresis (2DE) and mass spectrometry. We observed that P. acanthamoebae can infect all three morphological subtypes of the genus Acanthamoeba and that the proteome pattern of released P. acanthamoebae elementary bodies was always practically identical regardless of the Acanthamoeba strain infected. Moreover, by comparing proteome patterns of encysting cells from infected and uninfected Acanthamoeba cultures, it was shown that encystment is blocked by P. acanthamoebae at a very early stage. Finally, on 2D-gels of purified P. acanthamoebae from culture supernatants, a subunit of the NADH-ubiquinone oxidoreductase complex, that is, an enzyme that has been described as an indicator for bacterial virulence was identified by a mass spectrometric and bioinformatic approach.

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“…4A Minnikin et al (2010) that the sequences of peaks in Fig. 4 are characteristic of contaminating polymers based on polyethylene glycol (PEG) (Keller et al, 2008;Schiller et al, 2004) is a much more plausible explanation. The proposal by Mark et al (2011) is that an authentic MALDI-TOF spectrum (Fig.…”

Section: Mass Spectrometry In Detection Of Mycolic Acid Biomarkers Fomentioning

confidence: 99%

“…As suggested previously , an alternative explanation for the regular 44 amu spacing of the components is that the peaks are derived from a material incorporating polyethylene glycol repeating units. These polymeric polyethylene glycol-based preparations are in widespread industrial use and the risk of their appearance in mass spectra is well-known, as emphasized by, for example, by Keller et al (2008) and Schiller et al (2004), the latter reproducing a representative MALDI-TOF mass spectrum. Another general point, which comprehensively disqualifies the profiles in Figs.…”

Section: Mass Spectrometry In Detection Of Mycolic Acid Biomarkers Fomentioning

confidence: 99%