Separation of nicotine metabolites by capillary zone electrophoresis and capillary zone electrophoresis/mass spectrometry.

The use of capillary zone electrophoresis (CZE) and capillary zone electrophoresis/mass spectrometry (CZE/MS) has been demonstrated, in principle, for the separation of nicotine and nicotine metabolites. The buffer system developed for separation and detection by CZE/UV was modified for use in CZE/MS analysis. Several of the metabolites are isobaric and tandem mass spectrometric (MS/MS) techniques have been used to differentiate such analytes.

Hydrogen/deuterium exchange using a coaxial sheath-flow interface for capillary electrophoresis/mass spectrometry.

The interfacing of capillary electrophoresis (CE) with mass spectrometry (MS) is well established and may be accomplished by use of either a coaxial arrangement or by employing a liquid T-junction. In both these interfaces a make-up flow is introduced. This is required because of the mismatch in flow rates for capillary electrophoresis approximately nL/min and 'true' electrospray approximately 2-10 microL/min. Electrical connectivity may also be established where the liquid flows meet (the introduction of nanospray renders the use of make-up flow unnecessary). Hydrogen/deuterium (H/D) exchange occurs in solution when there are labile hydrogen atoms present in a molecule. The establishment of the presence and the number of such exchangeable hydrogen atoms may be of importance in the identification and differentiation of compounds. It may also be an aid in the structural elucidation of unknown materials. We have investigated the feasibility of carrying out H/D exchange via a CE/MS interface. This involved the addition of D2O to the sheath flow and our preliminary results showing the separations of drug substances, subsequently undergoing exchange, are presented.

Analysis of Bacitracin B using fast atom bombardment and tandem mass spectrometry.

Bacitracin is a mixture of polypeptide antibiotics produced by the action of Bacillus subtilis and Bacillus licheniformis. The mixture has previously been shown to contain at least ten components, of which only the major component, Bacitracin A, and its oxidized counterpart, Bacitracin F, have been fully structurally evaluated. Using fast atom bombardment ionization with tandem mass spectrometry, three isobaric components of one of the minor constituents of the mixture, Bacitracin B, have been structurally characterized, delineating the three single substitution sites within Bacitracin A where Ile has been replaced by Val.

Electron ionization-tandem mass spectrometry of glycosphingolipids. Part II. The identification of a carbohydrate sequence corresponding to a novel repetitive blood group A heptaglycosylceramide.

In a previous paper, the presence in human kidney vein tissue of a novel blood group A heptaglycosylceramide based on the type-3 carbohydrate chain GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-4Glc beta 1-1 Ceramide, was suggested based on thin-layer immunostaining and electron ionization mass spectrometry. Ions corresponding to a structure containing two deoxyhexoses, two hexosamines and three hexoses were identified, but no information was obtained from mass spectrometry concerning the carbohydrate sequence. In the present paper, we report the identification of carbohydrate sequence ions corresponding to a type-3 chain A heptaglycosylceramide by electron ionization-tandem mass spectrometry of a permethylated-reduced glycosphingolipid mixture isolated from human kidney vein tissue. The use of a microchannel-plate-array detector increased the sensitivity for collision-induced dissociation spectra by a factor of at least ten over a conventional electron multiplier.

Fast-atom-bombardment mass spectra of enkephalins.

The positive- and negative-ion mass spectra of [methionine]enkephalin and [leucine]enkephalin have been obtained by using a fast-atom-bombardment source described previously by Barber, Bordoli, Sedgwick & Tyler [(1981) J. Chem. Soc. Chem. Commun., in the press]. This technique has allowed the spectra to be obtained without conversion of the enkephalins into volatile derivatives. The fast-atom-bombardment spectra show good pseudo-molecular-ion sensitivity and fragmentation that can be interpreted on the basis of the known molecular structure.