Negative Ion Fast Atom Bombardment Research Articles

Hydrolyzed reactive dyes. Part 1: Analyses via fast atom bombardment and electrospray mass spectrometry

This paper provides a summary of results from the use of negative ion fast atom bombardment (FAB) and negative ion electrospray (ES) mass spectrometry to characterize dye structures remaining following the dyeing of cotton with reactive dyes. It was found that the ES method gave peaks of higher relative abundance in the molecular weight region and better signal to noise ratios than the FAB ionization process.

Identification of sulfoquinovosyl diacylglycerol as a major polar lipid inMarinococcus halophilusandSalinicoccus hispanicusand substitution with phosphatidylglycerol

The sulfonolipid sulfoquinovosyl diacylglycerol normally associated with photosynthetic membranes was identified as a major lipid in Marinococcus halophilus, Salinicoccus hispanicus ("Marinococcus hispanicus"), and Marinococcus sp. H8 (Planococcus sp. H8). Phosphatidylglycerol and 0%-10% cardiolipin accounted for the remaining polar lipids in these moderately halophilic, Gram-positive bacteria. Negative-ion fast atom bombardment mass spectrometry was used to quantify these three polar lipids from cells grown in media containing 0.03 to 4 mol NaCl/L. All strains revealed dramatic shifts in the ratio of sulfonolipid to phospholipid dependent on the salinity of the growth media, when grown in media with low phosphate content. Highest sulfonolipid content occurred during best growth in 0.5-2 mol NaCl/L, approaching 80%-90% of the total polar lipids. It was demonstrated that growth of M. halophilus in the presence of elevated phosphate and low sulfate blocked the shift to decreased phospholipids most notably during growth in 0.5-2 mol NaCl/L, without significant influence on growth. The data suggest that in low-phosphate media the influence of NaCl concentration on growth rate (and resulting demand for phosphate by competing pathways) is the primary factor responsible for exchange between phospholipid and sulfonolipid. We conclude that sulfoquinovosyl diacylglycerol, by substitution with phospholipids, contributes to the ability of these Gram-positive cocci to adapt to changing ionic environments. A comparison of 16S rRNA established a close similarity between Planococcus sp. H8 and M. halophilus.

Lewis acidity dependency of the electrochemical window of zinc chloride–1-ethyl-3-methylimidazolium chloride ionic liquids

Negative ion fast atom bombardment mass spectra (FAB-MS) recorded for ZnCl 2–1-ethyl-3-methylimidazolium chloride (ZnCl 2–EMIC) ionic liquids with various compositions indicate that various Lewis acidic chlorozincate clusters (ZnCl 3 −, Zn 2Cl 5 − and Zn 3Cl 7 −) are present in ZnCl 2–EMIC ionic liquids depending on the percentage of ZnCl 2 used in preparing the ionic liquids; higher ZnCl 2 percentage favors the larger clusters. Cyclic voltammetry reveals that the potential limits for a basic 1:3 ZnCl 2–EMIC melt correspond to the cathodic reduction of EMI + and anodic oxidation of Cl −, giving an electrochemical window of approximately 3.0 V which is the same as that observed for basic AlCl 3–EMIC ionic liquids. For acidic ionic liquids that have a ZnCl 2/EMIC molar ratio higher than 0.5:1, the negative potential limit is due to the deposition of metallic zinc, and the positive potential limit is due to the oxidation of the chlorozincate complexes. All the acidic ionic liquids exhibit an electrochemical window of approximately 2 V, although the potential limits shifted in the positive direction with increasing ZnCl 2 mole ratio. Underpotential deposition of zinc was observed on Pt and Ni electrodes in the acidic ionic liquids. At proper temperatures and potentials, crystalline zinc electrodeposits were obtained from the acidic ionic liquids.

Negative-ion electrospray ionization tandem mass spectrometry of N-phosphoryl amino acids and dipeptides.

The negative-ions of N-phosphoryl amino acids were studied by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The negative-ion ESI-MS/MS of N-phosphoryl amino acids showed characteristic fragmentation patterns different from those observed in the corresponding positive-ion ESI-MS/MS and negative-ion fast-atom bombardment mass spectra. For negative-ion ESI-MS/MS, a unique fragmentation from the N-terminal of N-phosphoryl amino acids or peptides containing a free beta-OH or CO(2)H group was observed to yield the characteristic fragment ion (RO)(2)P(O)O(-). The ease of the rearrangement depended on the position of the hydroxyl group in amino acids or peptides, and the N --> O rearrangement mechanism was proposed to involve the participation of the hydroxyl group. From previous solution-phase experiments and theoretical calculations, it was found that the beta-OH group was more active than gamma-OH, and the corresponding difference in negative-ion ESI-MS/MS was consistent with those previous findings.

Biomarker techniques to screen for bacteria that produce polyunsaturated fatty acids

The production of polyunsaturated fatty acids (PUFA) by bacteria has been firmly established for over two decades although it is still commonly ignored. Investigations of Antarctic sea ice have revealed a high diversity of novel bacterial taxa with the ability to produce PUFA. The majority are psychrophilic (requiring low temperatures for growth) and halophilic (requiring the presence of salts for growth), in contrast to the bacterial community present in the underlying water column. Specific fatty acids may be used as indicators of PUFA-producing bacteria in environmental samples. Structural studies of bacterial phospholipids have been particularly revealing in suggesting biomarkers specific for prokaryotic PUFA input. The use of negative ion fast atom bombardment tandem mass spectrometry for the analysis of bacterial phospholipids has identified species specific for certain groups of bacterial PUFA producers. The phylogeny of PUFA production in the γ- Proteobacteria also suggests the future use of PUFA genes for the assessment of marine bacterial biodiversity.

New Glycosphingolipids from the Marine Sponge Aplysinella rhax and Their Potential as Nitric Oxide Release Inhibitors

Several new glycosphingolipids were isolated by means of reversed-phase HPLC from the less-polar fraction of the methanol extract of the sponge Aplysinella rhax. Their structures, showing very close similarity, were elucidated by extensive NMR experiments including 1H,1H (COSY, TOCSY and ROESY) and 1H,13C (HMQC and HMBC) spectroscopy and chemical evidence. The molecular masses of the glycosphingolipids were determined by negative-ion fast-atom bombardment mass spectrometry, while HREIMS and HRFABMS provided important information for the identification of the fatty acids and sphingoid bases. The mixture of glycosphingolipids exhibited a good inhibitory activity on LPS-induced NO2− release by J774 A.1 macrophages.

Characterization of the Radical Product Formed from the Reaction of Nitric Oxide with the Spin Trap 3,5-Dibromo-4-Nitrosobenzene Sulfonate

Previously, 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS) has been used in combination with electron paramagnetic resonance (EPR) spectrometry to trap nitric oxide (NO•). The reaction between DBNBS and NO• yields a radical product which gives rise to an EPR signal consisting of three lines with an AN = 0.96 mT, but the structure of this product is unknown. A two-stage high-performance liquid chromatography fractionation was performed to isolate the radical product from the other components in the DBNBS/NO• reaction mixture. The fractions containing the radical product were identified by the presence of the three-line EPR signal, and then these fractions were analyzed by negative ion fast atom bombardment–mass spectrometry (FAB–MS). Collectively, the FAB–MS data suggested that the radical product is the monosodium electrostatic complex with the dianion, bis(2,6-dibromo-4-sulfophenyl) nitroxyl. Analysis of the Gaussian and Lorentzian linewidths of the EPR signal suggested that bis(2,6-dibromo-4-sulfophenyl) nitroxyl molecules may group together to form micelles. Further studies also indicated that significant amounts of nitrogen and nitrate were produced during the reaction between DBNBS and NO•. A reaction scheme consistent with these results is presented.

A 37-kDa peroxidase secreted from liverworts in response to chemical stress

A peroxidase was purified from the culture medium of a suspension culture of Marchantia polymorpha (liverwort) after treatment with bornyl acetate, which acts as a chemical stress agent to the cells. The peroxidase was characterised as a glycoprotein of molecular mass 37-kDa having a pI of about 10 and an optimal pH of 6.5. The peroxidase was thermally stable at 50°C for up to 60 min. The partial amino acid sequence of the peroxidase was determined and found to be dissimilar to the amino acid sequences of other higher plant peroxidases. The oxidative polymerization of lunularin by this peroxidase was examined and the formation of a dimer, a trimer and a tetramer was demonstrated by negative ion Fast Atom Bombardment (FAB)-mass spectroscopy of the reaction products.

Inactivation of the Peroxisomal Multifunctional Protein-2 in Mice Impedes the Degradation of Not Only 2-Methyl-branched Fatty Acids and Bile Acid Intermediates but Also of Very Long Chain Fatty Acids

According to current views, peroxisomal beta-oxidation is organized as two parallel pathways: the classical pathway that is responsible for the degradation of straight chain fatty acids and a more recently identified pathway that degrades branched chain fatty acids and bile acid intermediates. Multifunctional protein-2 (MFP-2), also called d-bifunctional protein, catalyzes the second (hydration) and third (dehydrogenation) reactions of the latter pathway. In order to further clarify the physiological role of this enzyme in the degradation of fatty carboxylates, MFP-2 knockout mice were generated. MFP-2 deficiency caused a severe growth retardation during the first weeks of life, resulting in the premature death of one-third of the MFP-2(-/-) mice. Furthermore, MFP-2-deficient mice accumulated VLCFA in brain and liver phospholipids, immature C(27) bile acids in bile, and, after supplementation with phytol, pristanic and phytanic acid in liver triacylglycerols. These changes correlated with a severe impairment of peroxisomal beta-oxidation of very long straight chain fatty acids (C(24)), 2-methyl-branched chain fatty acids, and the bile acid intermediate trihydroxycoprostanic acid in fibroblast cultures or liver homogenates derived from the MFP-2 knockout mice. In contrast, peroxisomal beta-oxidation of long straight chain fatty acids (C(16)) was enhanced in liver tissue from MFP-2(-/-) mice, due to the up-regulation of the enzymes of the classical peroxisomal beta-oxidation pathway. The present data indicate that MFP-2 is not only essential for the degradation of 2-methyl-branched fatty acids and the bile acid intermediates di- and trihydroxycoprostanic acid but also for the breakdown of very long chain fatty acids.

Characterization of Oligosaccharides of the Lactosamine Series Derived from Keratan Sulfates by Tandem Mass Spectrometry

Positive- and negative-ion fast-atom bombardment tandem mass spectrometry with collision-induced dissociation (FAB-CID-MS/MS) has been used in the characterization of di-and tetra-saccharides of the lactosamine series from keratan sulfates. FAB-CID-MS/MS of Galβ1-4GlcNAc (L1) exhibited strong fragment ions originating from ring cleavage at the reducing-terminal sugar moiety together with glycosidic bond-cleavage ions, whereas GlcNAcβ1-3Gal (K1) showed strong glycosidic bond-cleavage ions but no ring-cleavage ions. A series of ring-cleavage fragment ions was observed with members of the L-series which have free hydroxyl groups at the C1 and C3 positions. CID-MS/MS spectra of the [M + Na – SO3]+ion ( m/z 406) from L2 and the [M + Na − 2SO3]+ion ( m/z 406) from L4 were almost identical with the CID-MS/MS spectrum of the [M + Na]+ion ( m/z 406) from L1, which indicated that the sugar skeletons of L2 and L4 are the same as that of L1. On the other hand, the CID-MS/MS spectrum of the [M + Na – SO3]+ion ( m/z 508) from L4 did not resemble that of the [M + Na]+ion ( m/z 508) from L2. The former showed peaks that were additional to the peaks in the latter. Since these extra peaks were accounted for on the basis of the structure of L3 [Galβ1(6S)-4GlcNAc, S = sulfate], the in-source loss of sulfate groups by ester exchange upon FAB ionization takes place in a dual manner; one reaction at the non-reducing terminal sugar to give L2 and the other at the reducing-terminal sugar to give L3. The CID-MS/MS spectra were characteristic for the tetrasaccharides L1-L1, L2-L2 and L4-L4 while in-source fragmentation confirms the component disaccharides of each tetrasaccharide. The structure of a tetrasaccharide trisulfate was confirmed as L2–L4 and not L4–L2 by CID-MS/MS. Negative-ion FAB-CID-MS/MS spectra of the sulfated di-and tetra-saccharides showed a pattern similar to that of the positive-ion spectra. Subtraction of the CID-MS/MS spectrum of the [M – H]−ion of L2 [Galβ1-4GlcNAc(6S)] from that of the [M – H – SO3]−ion of L4 [Gal(6S)β1-4GlcNAc(6S)] gave several specific ions whose origins were nicely explained on the basis of the structure of L3. The structure of a pentasaccharide consisting of N-acetylneuraminic acid and a tetrasaccharide trisulfate was confirmed, on the basis of FAB-CID-MS/MS, as NeuNAcα2-6L2-L4.

Negative fast atom bombardment ionization of aromatic sulfonic acids: unusual sample-matrix interaction.

The most intense ion(s) in negative ion fast atom bombardment (FAB) mass spectra of 2- and 4-benzaldehyde sulfonic acid (BSA) in glycerol or 3-nitrobenzyl alcohol matrix corresponds to a covalent association of the analyte with one or two matrix molecules accompanied by the elimination of a molecule of water. The molecular ion [M - H](-), however, is of low abundance. The identity of the resulting ions [M + nA - H(2)O - H](-) (where M is the analyte and A is the matrix) was confirmed by exact mass measurement using the peak matching technique. These covalent matrix-analyte complexes were not observed when the sulfonic acid functionality in BSA was substituted with COOH, NO(2), and OH or when the sulfonic acid was in salt form. These observations indicate that the free sulfonic acid group in BSA is responsible for the covalent adduct formation. To our knowledge, analyte-matrix covalent association in negative ion FAB spectra of BSA has not been reported previously.

Chiral recognition of cellulose tris(5-fluoro-2-methylpheylcarbamate) toward (R)- and (S)-1,1′-bi-2-naphthol detected by negative ion fast-atom bombardment mass spectrometry

Chiral recognition between cellulose tris(5-fluoro-2-methylphenylcarbamate) (MW > 120,000) as a host compound and (R,S)-1,1'-binaphthol (MW 286) as a guest compound was investigated by fast-atom bombardment mass spectrometry (FAB-MS). The use of negative ion FAB-MS made it possible to obtain a very simple mass spectrum of the guest compound with a high signal-to-noise ratio. Additionally, when nitrophenyl octyl ether, which has no OH group, was utilized as matrix, chiral recognition between the host and the guest compounds was unequivocally detected. Copyright 1999 John Wiley & Sons, Ltd.

Analysis of saponins from black bean by electrospray ionization and fast atom bombardment tandem mass spectrometry.

Saponins from black bean (Vigna mungo L. Hepper) were analyzed using positive and negative ion fast atom bombardment mass spectrometry (FAB-MS) and liquid chromatography/mass spectrometry. Methanol was used to extract the saponins from defatted black bean, which was partially purified by extraction with n-butanol, and the extract was dialyzed with 3000 M(r) cut-off tubing. The dialyzate was analyzed using mass spectrometry. According to FAB-MS/MS, mixtures from black bean contain soyasaponin I as the predominant saponin. In addition, MS/MS analysis was performed in which the structures of saponins of black bean cotyledon were determined to be soyasaponin I, soyasaponin II, soyasaponin V, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl]complogenin (saponin A) and 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid (saponin B). For the black bean shell and the root of black bean sprout, analysis confirmed the saponins of soyasaponin I, soyasaponin II, soyasaponin V, saponin A, saponin B, acetylsoyasaponin A(4) and soyasaponin beta(g). Moreover, all the studied saponins were found in the stem and leaves of the black bean sprouts, except soyasaponin beta(g) and acetylsoyasaponin A(4), respectively.

Metabolites of A and E destruxins inGalleria mellonella larvae using negative-ion fast-atom bombardment mass spectrometry

Detoxification of E-destruxin into E-diol-destruxin, conjugated glutathionyl-E-destruxin, cysteinyl-E-destruxin, and phosphorylated E-destruxin, in vivo in Galleria mellonella, is demonstrated using negative-ion fast-atom bombardment (FAB) mass spectrometry. Copyright © 1999 John Wiley & Sons, Ltd.

Epitope dissection of receptor-active gangliosides with affinity for Helicobacter pylori and influenza virus.

Receptor-active gangliosides with affinity for Helicobacter pylori and influenza virus were chemically modified and analyzed by negative ion fast atom bombardment mass spectrometry (FAB MS) or electron ionization mass spectrometry (EI MS) after permethylation. Derivatizations included mild periodate oxidation of the sialic acid glycerol tail or conversion of the carboxyl group to primary alcohol or amides. The modified gangliosides were then tested for binding affinity using thin-layer plates overlaid with labeled microbes or microbe-derived proteins. Mild periodate oxidation, which shortens sialic acid tail without destruction of sugar cores, abolished or drastically reduced binding of H. pylori and avian influenza virus to sialyl-3-paragloboside (S-3-PG). The same effect was observed in the case of binding of the human influenza virus to receptor-active gangliosides of human leukocytes. Conversion of S-3-PG or leukocyte gangliosides to primary alcohols or amides also abolished the binding. However, mild periodate oxidation had no effect on binding of NAP (neutrophil-activating protein of H. pylori) to the active ganglioside.

Iron Salts in the Post-Metallization of Mordant Dyes

Iron (II) and iron (III) salts are used as mordanting agents in lieu of chromium ions, as a source reduction approach to eliminating chromium in dye effluents following the post-metallization of acid mordant dyes. Specifically, wool fabric is dyed with Mordant Yellow 8, Yellow 30, Orange 3, Orange 6, Red 7. Red 19, Blue 1, Blue 9, Blue 13, Brown 40, Black 1, and Black 11, then treated with iron salts. The complexes are characterized by negative ion fast-atom bombardment mass spectrometry and absorp tion spectrophotometry, and the after-treated fabrics are evaluated for lightfastness and washfastness. Mordant dyes possessing either ortho, ortho'-bis(hydroxy)- phenylazopyrazole or ortho-hydroxy-phenylazonaphthol substituted chromophoric sys tems form the corresponding 1:2 metal : dye complex and undergo significant improve ments in lightfastness and washfastness following metallization.

FAB-CID Mass Spectrometry of Imidazolone Derivatives Related to the Chromophore of Aequorea Green Fluorescent Protein.

Positive and negative ion fast atom bombardment tandem mass spectrometry (FAB-CID MS/MS) has established the fragmentation pattern of the 18 imidazolone derivatives which are related to the structure of the GFP (green fluorescent protein) chromophore in the jellyfish Aequorea bioluminescence. Ring cleavage of the C5-N1 and C2-N3 bonds is characteristics of these compounds, but for NH derivatives cleavage of the methylidene group as well as the C4-C5 and C2-N3 bonds also occurred in the positive ion mode, while ring cleavage of the C2-N3 and C4-C5 bonds occurred commonly in the negative ion mode. On the basis of the CID-MS/MS (collision induced dissociation tandem mass spectrometry) the structures of protonated molecules produced upon FAB are discussed.When the structure of the fragment ion has a p-quinonoid moiety, distinct peaks due to radical anion species such as [M-H-CH3]-· are observed in their CID-MS/MS of parent anions [M-H]-, which seems to be characteristics of the conjugated p-hydroxyphenyl structures.

Study of sinapinyl but-3-enylglucosinolate (boreavan A) and related compounds by mass spectrometry

Electron impact (EI), positive and negative ion fast atom bombardment (FAB) combined with tandem mass spectrometry was used for the structural elucidation of sinapinyl but-3-enylglucosinolate (boreavan A). The EI mass spectra showed the presence of ions due to the sinapic acid moiety. Protonated and deprotonated quasi-molecules and some structurally significant fragment ions due to sulphate were observed in the FAB mass spectra. The tandem mass spectra gave information for the identification of the main building blocks and the sequence ions of the sinapinium cation in boreavan A, and also showed that the number of side chains present in the glucosinolate moiety has a potential influence on the location of the anion part of boreavan A. © 1997 John Wiley & Sons, Ltd.

Synthesis and properties of a series of new asymmetrical tetrathiafulvalene derivatives

A series of new asymmetrically substituted tetrathiafulvalene (TTF) derivatives, a charge transfer (CT) complex, and several related symmetrical TTF derivatives were synthesized. The compounds were characterized by elemental analysis, 1H NMR spectra, IR spectra, and electron ionization (EI) or negative-ion fast atom bombardment (FAB) mass spectral analysis. UV-Vis spectra of the new asymmetrical TTF derivatives and the CT complex in solution were investigated. In addition, mixed conducting Langmuir-Blodgett (LB) films were constructed from the asymmetrical TTF derivatives by admixing with an equimolar arachidic acid.

Fast Atom Bombardment Mass Spectra ofN-Phosphorylated Peptide Analogs

A series of N-(N-alkyl)- and N-(O-alkyl)phosphopeptide analogs were determined by positive and negative ion fast atom bombardment mass spectrometry and their fragmentation pathways were investigated. Their mass spectra gave abundant [MH - NH z R'] + , [MH - HOR] + , [MH - H 2 O] or [M - H - NH 2 R'] - , [M - H - HOR] - ions, which contained pentavalent tricoordinate phosphorus ions through the loss of amine or water. In the positive ion mass spectra, + NH 3 R' and + NH 3 CHRCONHR' were found, while [MH - NH 2 CHRCONHR'] + was suppressed. In the negative ion mass spectra, the pseudomolecular ion [M - H] - was the base peak, and almost all the fragment ions contained a phosphoryl group.