Frit-fast Atom Bombardment Mass Research Articles

Detection of new spider toxins from a Nephilengys borbonica venom gland using on-line μ-column HPLC continuous flow (FRIT) FAB LC/MS and MS/MS

Spider venom glands store various novel neurotoxic acylpolyamines which present potent and irreversible inhibition of the glutamatergic synapses. We have developed a new highly sensitive analytical method to detect and characterize structures of those neurotoxins stored in a single venom gland using micro bore column high performance liquid chromatography (HPLC)-continuous flow FRIT fast atom bombardment mass spectrometry (HPLC-FAB/MS) and tandem mass spectrometry (MS/MS) array detection system. The high-energy collision induced dissociation (CID) spectra of sodium cationized spider toxins produced very strong structurally informative product ions which afforded the location of nitrogen atoms and the connectivity of methylene units within the polyamines. This methodology permitted detection of 40 amino acid containing acylpolyamines in the venom of Nephilengys borbonica from which structures of only five compounds were previously known.

Detection and characterization of modified nucleosides in serum and urine of uremic patients using capillary liquid chromatography–frit-fast atom bombardment mass spectrometry

To determine RNA metabolism in uremia, capillary liquid chromatography–frit-fast atom bombardment mass spectrometry was employed for the characterization of ribonucleosides in serum and urine of uremic patients, and the profiles were compared with those of healthy subjects. We have characterized 20 nucleosides in serum and 23 nucleosides in urine from both healthy subjects and uremic patients; most of them were modified nucleosides derived from tRNA breakdown products. Four metabolites derived from allopurinol were detected as exogenous nucleosides in patients receiving allopurinol; these include allopurinol-1-riboside, oxipurinol-1-riboside, oxipurinol-7-riboside and a unknown oxipurinol riboside. The endogenous and exogenous ribonucleosides were retained at higher levels in uremic serum, and may play a contributory role as toxins responsible for clinical symptoms of uremia.

On-line solid-phase extraction liquid chromatography-continuous flow frit fast atom bombardment mass spectrometric and tandem mass spectrometric determination of hydrolysis products of nerve agents alkyl methylphosphonic acids by p-bromophenacyl derivatization

For proof of the presence of chemical warfare agents sarin, soman and VX, a rapid, accurate and sensitive method which allows us to determine their hydrolysis products ethyl methylphosphonic acid, isopropyl methylphosphonic acid and pinacolyl methyl phosphonic acid was explored by using continuous flow frit fast atom bombardment (FAB) LC–MS and LC–MS–MS. After derivatization of analytes with p-bromophenacyl bromide, LC–MS–MS analyses for screening were performed by a flow injection method. The three alkyl methylphosphonic acids (AMPAs) were eluted within 5 min, and the detection limits for the three AMPAs ranged from 1 to 5 ng/ml. For confirmation of the screening results, LC–MS–MS analysis with chromatographic separation was conducted by using a narrow bore column. The three AMPAs were all eluted with excellent separation within 25 min, and the detection limits ranged from 1 to 20 ng/ml. Quantitative measurement was performed by LC–MS in selected ion monitoring (SIM) mode with chromatographic separation. Linear calibration curves were obtained for the three AMPAs and the detection limits ranged from 0.5 to 3 ng/ml. The relative standard deviation for peak area ranged from 3.4 to 6.0% at 50 ng/ml for the three AMPAs.

The Analysis of Some Corticosteroids and Corticosteroid Esters by Liquid Chromatography Coupled with Frit Fast-atom Bombardment Mass Spectrometry

The Analysis of Some Corticosteroids and Corticosteroid Esters by Liquid Chromatography Coupled with Frit Fast-atom Bombardment Mass Spectrometry

Highly sensitive and rapid determination of theophylline, theobromine and caffeine in human plasma and urine by gradient capillary high-performance liquid chromatography-frit-fast atom bombardment mass spectrometry.

A sensitive and reliable analytical procedure has been established for the detection of theophylline (TH), theobromine (TB) and caffeine (CA) in human plasma and urine by gradient capillary high-performance liquid chromatography (HPLC)-frit-fast atom bombardment mass spectrometry (FAB-MS) (LC-frit-FAB-MS). Two capillary columns and a column-switching valve were used in this LC system to allow all of the sample injected to be introduced into the MS system. 7-Ethyltheophylline was used as the internal standard (I.S.). The xanthines in the specimen were extracted with an Extrelut column. The lowest detected amount was ca. 5 ng/ml using this method.

Detection of ribose-methylated nucleotides in Pyrodictium occultum tRNA by liquid chromatography--frit-fast atom bombardment mass spectrometry.

Ribose-methylated dinucleotides of the type NmpN' derived from digestion of tRNA with RNase T2 were separated and characterized by directly combined liquid chromatography--mass spectrometry (LC-MS) with a continuous-flow frit-fast atom bombardment (frit-FAB) interface. Prediction of NmpN' peaks was readily made by comparison of the LC profile with that of comparative nuclease P1 digest. The identity of the candidate peaks including NmpN' was further recognized by the mass spectra, in which NmpN' showed intense molecular-related ions, in addition to sequence-specific fragment ions, to verify the chemical structures in both positive- and negative-ion modes. The method was applied to screening NmpN' (and NmpN' mpN") in tRNA from the extremely thermophilic archaeon Pyrodictium occultum.

Analysis of urinary and biliary metabolites of (+)-4-[4-(4-methylphenyl)phenylmethoxy-1-piperidinyl]butyric acid in rats by liquid chromatography-frit-fast atom bombardment mass spectrometry.

The urinary and biliary metabolites of (+)-4-[4-(4-methylphenyl)phenylmethoxy-1-piperidinyl]butyric acid [(+)-MPPB] were examined in rapid-metabolizing (RM) and slow-metabolizing (SM) male Sprague-Dawley rats by means of liquid chromatography-frit-fast atom bombardment mass spectrometry. In the RM-phenotyped rats, unchanged (+)-MPPB could not be detected in urine or bile, but 4-carboxyphenyl-MPPB was detected in bile. In the SM-phenotyped rats, unchanged (+)-MPPB was detected in bile and unchanged (+)-MPPB and beta-oxidized MPPB in urine. Thus, the inter-individual difference in (+)-MPPB metabolism in rats was confirmed in vivo.

Dehalogenation reactions in frit fast‐atom bombardment mass spectrometry of substituted hydroquinones

AbstractThe reduction reaction consisting in the substitution of a chlorine by a hydrogen atom, already known in fast‐atom bombardment (FAB) mass spectrometry, has been established for the first time in Frit FAB mass spectrometry in the case of 2‐chloro‐1,4‐hydroquinone and 2,5‐dichloro‐1,4‐hydroquinone. Comparison of the spectra obtained with mobile phases containing either glycerol or meta‐nitrobenzyl alcohol has been performed for both compounds.

Resolution of 4-(4-chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4yl)-1(2H)-phthalazinone enantiomers in plasma with frit-FAB LC—MS using a conalbumin column

A new column-switching method for analysis of drug enantiomers in plasma has been developed with liquid chromatography—frit fast atom bombardment mass spectrometry in combination with a chiral resolution column, which consists of conalbumin (egg-white glycoprotein) immobilized on silica gel and can be used in the reversed-phase separation mode. This method makes it possible to inject a large volume of deproteinized plasma and obtain resolution of drug enantiomers with high sensitivity. The optimum mobile phase, including a non-volatile buffer such as phosphate buffer, for separation of drugs from a large amount of endogenous compounds can be used, because of inclusion of a trapping column with a desalting function. This method is very simple and rapid, and should be very powerful in studies requiring high-sensitivity analysis with chiral separation of drugs from biological samples such as plasma.

Rapid analysis of enzymatic digests of a bacterial protease of the subtilisin type and a “bio-engineered” variant by high-performance liquid chromatography—frit fast atom bombardment mass spectrometry

Amino acid sequencing of a subtilisin-type bacterial protease and a bio-engineered variant was carried out by investigating various enzymatic digests using HPLC-frit fast atom bombardment MS methods. The fast atom bombardment mass spectral data allowed rapid identification of the enzymatically generated peptides and differentiation between both proteins. The feasibility of determining the positions and nature of mutations in the amino acid sequence depends mainly on the size of the peptides containing the modifications.

Rapid confirmation and revision of the primary structure of bovine serum albumin by ESIMS and frit-FAB LC/MS

Incorrectness of the amino acid sequence of bovine serum albumin (BSA) was suggested from the observed molecular weight of BSA obtained by electrospray ionization mass spectrometry (ESIMS). Lack of a tyrosine residue in the position of 156th was found rapidly, by the combination of frit-fast atom bombardment mass spectrometry/liquid chromatography (Frit-FAB LC/MS), automated Edman degradation and tandem mass spectrometry (MS). Then it turned out that BSA is composed of 583 amino acid residues, and that its average molecular weight is not 66267.1, and it is corrected to 66430.3. Moreover the amino acid sequence of the positions of 94th and 95th was corrected to -QE- by using automated Edman degradation method.