An investigation and identification of polysaccharides isolated from archeological specimens
SummaryPolymeric compounds have been isolated from archeological specimens (fragments of Central Asian paintings of the 2nd-19th centuries). A comparison of their IR spectra with the spectra of plant gums has shown that they are polysaccharides which have remained undestroyed for up to 1800 yr. In some cases it has been possible from the IR spectra and composition of the extracted polysaccharides to provisionally identify sourcherry or apricot gum, of which these polysaccharides were components.
A two-dimensional scanner for radiochromatograms employing an electron multiplier detector in vacuo
Abstract A step scanner for the measurement of both one- and two-dimensional distributions of radionuclides in paper or thin-layer chromatography has been constructed and tested. Different versions of a miniaturized channel electron multiplier have been applied as detectors. A description is given of the principle of operation for this detector type, the vacuum scanner, and the way of data presentation. Performance tests have been made with calibrated standards of 3 H and 14 C in the form of poly(methyl methacrylate) pieces with known electron emission defined as the number of electrons emitted per second per cm 2 . Several thin-layer media have been used, mostly with directly applied spots of [ 3 H]- or [ 14 C]glucose solutions. Upon drying, spots of activities down to 5 nCi could easily be detected (spot areas were approximately 0.7 cm 2 ). A resolution of 1 mm could easily be achieved in the one-dimensional scans. Some more results of a somewhat preliminary nature are reported. Some possible alternative for the recording of measurements which use the channel electron multiplier detector are mentioned. The use of scanning by electron multipliers as a method for radiochromatography has the advantages that the sample is neither damaged nor contaminated compared with conventional techniques which, for example, employ the admixture of wet (or dry) scintillators. It is felt that these advantages for certain applications more than compensate for the fact that the technique a vacuum of 5 ·10 −4 torr.
Dünnschichtchromatographie der kohlehydrate
Trennungen von niederen Hydroxy-Oxoverbindungen, die als Abbauprodukte von Kohlehydraten auftreten, von Zuckersauren und ihren Lactonen sowie Zuckerosazonen mit Hilfe der Dunnschichtchromatographie werden beschrieben. Zur Verbesserung der Elutionstechnik wird eine neue Anordnung angegeben, die auch eine Steigerung der Empfindlichkeit bei der Identifizierung ermoglicht.