Thin-layer chromatography of malto-oligosaccharides.
Abstract Procedures for the separation, location and elution of malto-oligosaccharides are described. Best separations were obtained on glass plates (20 × 46 × 0.5 cm) coated with Kieselguhr G, serially developed in solvents of varying proportions of x-butanol, pyridine and water. Major zones were temporarily visualized by exposing the plates to iodine vapors. The located zones were eluted from the thin-layer plates into fiberglass filter pieces with water. Radioactivity of the zone can be determined directly by placing the filter in a toluene-based scintillation fluid and counting in a scintillation counter. After radioactivity determination, the carbohydrates can be eluted from the filter with water and quantitatively measured.
A lipid linked oligosaccharide which contains hexosamine, mannose and glucose
SummaryPrevious work showed that liver microsomes catalyze the transfer of glucose from dolichol monophosphate glucose to an endogenous acceptor believed to be a dolichol pyrophosphate derivative of an oligosaccharide. This oligosaccharide has now been prepared on a larger scale so as to permit the determination of its sugars. The purification procedure includes, as a last step, a thin layer chromatography on kieselguhr-silica gel to obviate glucose-containing contaminants. After complete hydrolysis mannose, glucose and a small amount of hexosamine were detected.
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.