Robert S. Bordoli

High sensitivity collisionally-activated decomposition tandem mass spectrometry on a novel quadrupole/orthogonal-acceleration time-of-flight mass spectrometer.

Consideration of the special problems encountered in ultra-high sensitivity biopolymer sequencing studies has led to the development of a novel quadrupole/erthogonal-acceleration time-of-flight tandem mass spectrometer described for the first time here. The performance characteristics of this new geometry are demonstrated, including fully resolved daughter-ion spectra with mass accuracies of 0.1 dalton, which allow removal of interpretation ambiguities and easy differentiation of charge states even in weak collisionally-activated decomposition tandem mass spectra. The instrument has been applied to a variety of biopolymer research problems, including the structure determination of major histocompatibility complex peptide antigens using liquid chromatography/electrospray mass spectrometry and nanoflow-electrospray tandem mass spectrometry, and sequencing capability in the low-femtomole and attomole ranges is demonstrated.

Fast atom bombardment: A new mass spectrometric method for peptide sequence analysis

Abstract We have studied a selection of peptides using a new mass spectrometric ionisation technique - fast atom bombardment (FAB). We define the fragmentation pathways observed and comment on the utility in sequence analysis. A simple acetylation experiment is shown to aid rapid sequence assignment.

Fast atom bombardment of solids (F.A.B.): a new ion source for mass spectrometry

A new method for obtaining high-quality mass spectra of molecules which previously were difficult or impossible to study by ionisation methods is described

Sequence dependent fragmentation of peptides generated by MALDI quadrupole time-of-flight (MALDI Q-TOF) mass spectrometry and its implications for protein identification.

A study has been undertaken to evaluate the usefulness of MALDI Q-TOF data for protein identification. The comparison of MS data of protein digests obtained on a conventional MALDI TOF instrument to the MS data from the MALDI Q-TOF reveal peptide patterns with similar intensity ratios. However, comparison of MS/MS Q-TOF data produced by nanoelectrospray versus MALDI reveals striking differences. Peptide fragment ions obtained from doubly charged precursors produced by nanoelectrospray are mainly y-type ions with some b-ions in the lower mass range. In contrast, peptide fragment ions produced from the singly charged ions originating from the MALDI source are a mixture of y-, b- and a-ions accompanied by ions resulting from neutral loss of ammonia or water. The ratio and intensity of these fragment ions is found to be strongly sequence dependent for MALDI generated ions. The singly charged peptides generated by MALDI show a preferential cleavage of the C-terminal bond of acidic residues aspartic and glutamic acid and the N-terminal bond of proline. This preferential cleavage can be explained by the mobile proton model and is present in peptides that contain both arginine and an acidic amino acid. The MALDI Q-TOF MS/MS data of 24 out of 26 proteolytic peptides produced by trypsin or Asp-N digestions were successfully used for protein identification via database searching, thus indicating the general usefulness of the data for protein identification. De novo sequencing using a mixture of 16O/18O water during digestion has been explored and de novo sequences for a number of peptides have been obtained.

Ionization and Fragmentation of Neutral and Acidic Glycosphingolipids with a Q-TOF Mass Spectrometer Fitted with a MALDI Ion Source

This paper reports the use of a quadrupole time-of-flight (Q-TOF) mass spectrometer fitted with a matrix-assisted laser desorption/ionization (MALDI) ion source for the analysis of neutral and acidic glycosphingolipids. All compounds gave strong [M + Na]+ ions with 2,5-dihydroxybenzoic acid as the matrix, with no loss of sensitivity with increasing mass as was observed from the corresponding ions produced by electrospray. Neutral glycosphingolipids showed negligible in-source fragmentation but sialylated compounds fragmented by loss of sialic acid. However, these losses were not accompanied by unfocused post-source-decay ions as observed with MALDI-reflectron-TOF instruments. The MS/MS spectra were almost identical to those obtained by electrospray. Fragmentation of all compounds was mainly by glycosidic cleavage to give ions, both with and without the ceramide moiety, which defined the carbohydrate chain sequence. Weak ions which defined the sphingosine chain length and abundant ions, produced by loss of the acyl chain, were present when this chain contained a 2-hydroxy group. The technique was applied to the identification of ceramide— trihexosides present in tissues from mice genetically modified to model one of the glycolipid storage diseases (Fabry disease).

Fast atom bombardment mass spectrometry of human proinsulin

Abstract The observation of protonated molecular species from human proinsulin obtained by fast atom bombardment mass spectrometry is reported.

Fast atom bombardment mass spectrometry of bleomycin A2 and B2 and their metal complexes.

Abstract The new mass spectrometric technique of fast atom bombardment is applied to the analysis of bleomycins either separately or in mixtures. The spectra are reproducible and afford valuable analytical data and structurally significant fragmentation patterns on these important antibiotics. The procedures outlined have also enabled the characterisation of various metal complexes.

Fast atom bombardment mass spectrometry (FABMS). A study of surface coverage effects in FABMS

A study of various surfactants using FABMS and surface tension measurements is described. A correlation between surface structure and FAB mass spectral response is reported with its possible significance in the ionisation mechanism.

The structure(s) of pyridinoline(s)

Abstract The structure of pyridinoline, a tri-functional cross-linking amino-acid from collagen, has been established by fast atom bombardment mass spectrometry (FABMS). An analogue, lacking the 3-hydroxyl group, has been isolated, and characterised by FABMS, electrophoresis and ultraviolet spectroscopy.

Fast Atom Bombardment mass spectra of involatile sulphonated and phosphonated azo dyestuffs

Abstract Positive and negative ion Fast Atom Bombardment mass spectra have been obtained for involatile mono- and disazo dyestuffs, containing up to five sulphonate and phosphonate groups. The spectra are discussed with special reference to the ions formed by cleavage of the azo linkages in both the mono- and disazo compounds. Characteristic fragment ions are also found for a compound containing a pyrazolone ring.