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- Breimer, Michael, 1951, et al.
(author)
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Selected ion monitoring of glycospingolipid mixtures. Identification of several blood group type glycolipids in the small intestine of an individual rabbit.
- 1979
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In: Biomedical mass spectrometry. - : Wiley. - 0306-042X .- 1096-9888. ; 6:6, s. 231-41
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Journal article (peer-reviewed)abstract
- A novel application of selected ion monitoring was used for a mixture of non-acid glycosphingolipids of one rabbit small intestine. Earlier studies of permethylated and permethylated-reduced (LiAIH4) derivatives of model compounds have revealed a specificity and abundance of saccharide ions (terminal monosaccharide(s), disaccharide, trisaccharide, etc., and all sugars plus fatty acid) and of ceramide fragments that permit a conclusive detection of separate glycolipid species in a mixture. The sample (50-200 micrograms) was evaporated slowly (1-5 degrees C min-1 from 150-350 degrees C) from the direct inlet probe of an MS 902 mass spectrometer (electron ionization). Mass spectra with fragments up to about m/z 200 were collected on-line by a computer system. A successive partial separation was obtained for glycolipids with from one up to seven sugars. The structures of eight different compounds were identified. They all had 16:0, 22:0 and 24:0 2-hydroxy fatty acids and 18:0 trihydroxy base (phytosphingosine) as major ceramide components. The dominating complex glycolipid was a hexaglycosylceramide with a blood group B type of sequence. A blood group A type sequence was found in a second hexaglycosylceramide. In support of this, the native mixture showed blood group A and B activity. An intense peak, m/z 182, collected from methylated derivatives were evidence for a dominating type 2 carbohydrate chain of the core tetrasaccharide.
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| 3. |
- Buras, Bronislav, et al.
(author)
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A high-pressure cell for neutron crystal spectrometry
- 1977
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Reports (other academic/artistic)abstract
- Three fixed-scattering-angle methods for neutron scattering powder measurements using double- and triple-axis crystal spectrometers were tested: (1) the analyzer-scan method (AS), (2) the monochromator-scan method (MS), and (3) the monochromator-analyzer-scan method (MAS). A high-pressure cell, primarily for use in powder diffraction measurements, with scattering angles of 30o, 60o, 90o and 120o and a sample volume of about 0.8 cm3 was constructed and used in conjunction with the MS and MAS methods. At room temperature, this cell makes it possible to make measurements at pressures up to about 40 kbar and up to about 30 kbar at 300° C. The report includes a description of the diffraction methods and of the high-pressure cell. A few examples of experimental results are also given.
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