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Table 3 Fragmentation patterns of signals at m/z 904.5, m/z 905.5, m/z 888.6 and m/z 882.6 obtained in the MS-spectra of Se°-nanoparticle samples and of particle sample extracts

From: Inhibition of bacteriochlorophyll biosynthesis in the purple phototrophic bacteria Rhodospirillumrubrum and Rhodobacter capsulatus grown in the presence of a toxic concentration of selenite

Analytes ∗

Precursor ion m/z

Product ions

    
  

1st

2nd

3rd

4th

  

m/z

Intensity (% max.)

m/z

Intensity (% max.)

m/z

Intensity (% max.)

m/z

Intensity (% max.)

BChl ap Reference

910.5

632.2

100

—

—

—

—

—

—

BChl ag Particle samples R. rubrum

904.5

632.2

100

572.2

6.4

—

—

499.2

12.2

Bphe ap Reference

888.6

610.3

100

549.3

28.1

537.3

11.1

477.3

14.1

Bphe ap Particle sample extracts Rba. capsulatus

888.6

610.3

100

549.3

22.1

537.3

16.7

477.3

14.3

Bphe ap. Particle sample extracts R. rubrum

888.6

610.3

100

550.3

15.5

537.3

12.6

477.3

10.9

Bphe ag. Particle samples R. rubrum

882.6

610.3

100

551.3

12.1

537.3

16.9

477.3

13.6

Bphe ag. Particle sample extracts R. rubrum

882.6

610.3

100

549.3

16.8

537.3

12.0

477.3

14.7

  1. Tandem MS-spectra of MS-signals obtained for particle samples or particle sample extracts were compared with those of the references BChl ap and BPhe ap. Note that in each MS/MS-spectrum the most intense signal was for the loss of a 278.3 m. u. fragment or of a 272.3 m. u. fragment. As the mass of these fragments exactly corresponded to that of the phytyl side chain or the geranylgeranyl side chain, respectively (Fig. 2), these results confirmed that each of these MS-signals represented a BChl (BChl ap or BChl ag) or a BPhe (BPhe ap or BPhe ag) molecule.
  2. *Identified according to the mass values obtained in the MS-spectra