Fast Atom Bombardment Mass Spectrometric Characterization of Poly(O-Toluidine)

1991 ◽  
Author(s):  
K. Balasaunmugam ◽  
K. G. Owens ◽  
K. F. Hsueh ◽  
P. Hoontrakul ◽  
M. A. Olsen
2002 ◽  
Vol 57 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Thomas Dülcks ◽  
Walter Grahn ◽  
Hans-Hermann Johannes ◽  
Ulf Lawrentz ◽  
Miriam Rittner ◽  
...  

Fast atom bombardment (FAB) has been used for mass spectrometric characterization of oligomeric cyanines and squaraines of the indole series which are linked by different aromatic spacers. Markedly different results were obtained for the oligomers and for the corresponding monomers. In addition to the expected mono-anions and mono-cations, ions of high relative abundance were detected which can only be explained on the basis of FAB-induced chemical reactions of the initial oligomers. Formation of allenes, hydrogenation and dehydrogenation, respectively, is characteristic for this class of compounds under FAB-conditions.


1998 ◽  
Vol 9 (2) ◽  
pp. 141-154 ◽  
Author(s):  
P. R. Das ◽  
B. N. Pramanik

1993 ◽  
Vol 76 (4) ◽  
pp. 913-917
Author(s):  
Randall J Baker

Abstract Fast atom bombardment (FAB) mass spectrometry (MS) is used to characterize the γ-hydroxy carboxylic acid (γ-HCa) formed from base hydrolyzed γ-lactone at room temperature. Acidification of this base hydrolyzed solution reconverts the γ-HCa back to γ-lactone. Mass shift differences between tetramethylammonium (TMA+) and Na+ ion-pairs with the anionic γ-HCarboxylate(–) (γ-HC(–)) are used to confirm molecular ion identifications. FAB ionization was required to provide mass characterization of the γ-HCa. Electron ionization (El) MS of the γ-HCa was unsuccessful and reconverted γ-HCa back to γ-lactone because of complete thermally induced dehydration. The present paper suggests structures for El fragmentation that support the molecular structure of γ-lactone.


1992 ◽  
Vol 38 (8) ◽  
pp. 1444-1448 ◽  
Author(s):  
M De Caterina ◽  
P Esposito ◽  
E Grimaldi ◽  
G Di Maro ◽  
F Scopacasa ◽  
...  

Abstract We describe an analytical protocol for characterizing the molecular structure of hemoglobin (Hb) Lepore variants by using two different mass-spectrometric approaches. The first method consists of direct examination of the chromatographically separated hybrid globins by electro-spray mass spectrometry; the variant Lepore globin is identified through the accurate determination of its molecular mass. Alternatively, the anomalous globins are digested with trypsin and their structures are determined by fast atom bombardment mass-spectrometric analysis of the peptide mixture. The application of this procedure to the identification of Hb Lepore Boston and Hb Lepore Baltimore is described.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2123
Author(s):  
Makuachukwu F. Mbaegbu ◽  
Puspa L. Adhikari ◽  
Ipsita Gupta ◽  
Mathew Rowe

Determining gas compositions from live well fluids on a drilling rig is critical for real time formation evaluation. Development and utilization of a reliable mass spectrometric method to accurately characterize these live well fluids are always challenging due to lack of a robust and effectively selective instrument and procedure. The methods currently utilized need better calibration for the characterization of light hydrocarbons (C1–C6) at lower concentrations. The primary goal of this research is to develop and optimize a powerful and reliable analytical method to characterize live well fluid using a quadruple mass spectrometer (MS). The mass spectrometers currently being used in the field have issues with detection, spectra deconvolution, and quantification of analytes at lower concentrations (10–500 ppm), particularly for the lighter (<30 m/z) hydrocarbons. The objectives of the present study are thus to identify the detection issues, develop and optimize a better method, calibrate and QA/QC the MS, and validate the MS method in lab settings. In this study, we used two mass spectrometers to develop a selective and precise method to quantitatively analyze low level lighter analytes (C1–C6 hydrocarbons) with masses <75 m/z at concentrations 10–500 ppm. Our results suggest that proper mass selection like using base peaks with m/z 15, 26, 41, 43, 73, and 87, respectively, for methane, ethane, propane, butane, pentane, and hexane can help detect and accurately quantify hydrocarbons from gas streams. This optimized method in quadrupole mass spectrometer (QMS) will be invaluable for early characterization of the fluid components from a live hydrocarbon well in the field in real time.


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