Chromatographie zur Bestimmung der Molmassen- und Teilchengrößenverteilung von Polymeren

Klein, Joachim; Kulicke, Werner‐Michael; Hollmann, Jens

doi:10.1007/978-3-642-72167-0_9

Cited by 5 publications

(5 citation statements)

References 11 publications

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“…In contrast to the elution diagrams of, e.g., bovine serum albumine (BSA), polystyrene lattices and pullulane which showed a quite smooth elution signal, in Figure the elution diagrams of the cationic starches are not smooth but jagged. − …”

Section: Resultsmentioning

confidence: 92%

“…In contrast to the elution diagrams of, e.g., bovine serum albumine (BSA), polystyrene lattices and pullulane which showed a quite smooth elution signal, in Figure 5 the elution diagrams of the cationic starches are not smooth but jagged. [24][25][26] We have been able to exclude that these jagged signals are due to detector noises. The jagged signals in all elution diagrams of the cationic starches are potentially due to adsorption phenomena on the semipermeable membrane.…”

Section: Determination Of the Molar Mass And Size Distribution By Asy...mentioning

confidence: 99%

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Cationic Starches as Substitute for Synthetic Cationic Flocculants in Solid−Liquid Separation of Harbor Sludge

Shirzad-Semsar

Scholz

2007

J. Phys. Chem. B

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Harbor sludge (about 25% total solid) has to be dredged to keep the waterways free. Thus, annually 1.2 million m3 of dredged material has to be cleaned. For this process, three different synthetic flocculants with optimal molar masses, ionogenities, and concentrations are added in order to get a good dewatering efficiency and shear strength of the flocs. But as synthetic flocculants bring about unwanted fish toxicity and insufficient biodegradability, this study intends to check whether these flocculants can successively be substituted by cationic starches which have already been proven to be less toxic than synthetic flocculants. Five different starch derivatives with an average degree of substitution higher than 0.5 were characterized, especially in terms of the molar mass and coil size distribution, and flocculation tests, zeta potential measurements and filtrate turbidity tests were carried out in order to create optimum flocculation conditions. The flocculation and dewatering measurements clearly show that the synthetic cationic flocculant PA (0.2 kg/tTS) can be best substituted by cationic starch KS 2 (c = 0.1 kg/tTS, Mw = 1.1 e+08). For substitution of PTAC (c = 0.3 kg/tTS) by cationic starches, we observed that a maximal dewatering efficiency is reached with an approximately 3-fold dose of KS 1 (1 kg/tTS, Mw = 8.1 e+07).

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Section: Resultsmentioning

confidence: 92%

Section: Determination Of the Molar Mass And Size Distribution By Asy...mentioning

confidence: 99%

Cationic Starches as Substitute for Synthetic Cationic Flocculants in Solid−Liquid Separation of Harbor Sludge

Shirzad-Semsar

Scholz

2007

J. Phys. Chem. B

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“…Die Lichtstreumessung wurden an einer kombinierten Anlage aus SEC, MALLS und DRI durchgeführt [4]. Die Chitosanproben wurden in einem 0,5 M Essigsäure/0,2 M Natriumac- …”

Section: Lichtstreuungunclassified

Das Verfahren zur Chitosan‐Gewinnung aus dem baltischen Krebs Gammarus lacustris

Grigoryeva

Mezenova

2007

Chemie Ingenieur Technik

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“…Light-scattering measurements were performed using a coupled system of various apparatuses consisting of an SEC unit, a multiangle laser light scattering photometer (Dawn DSP; Wyatt Technology Corp., Santa Barbara, CA; ϭ 633 nm), and a concentration detector (Shodex RI-71; Showa Denko, Tokyo, Japan) at 25°C (15,16,18,20). Chitosan samples were dissolved in an eluent (0.1 vol% CF 3 COOH, 0.1 mol/liter NaCl) by shaking (12 h) and polymer solutions (1 mg/ml) were filtered using a 0.45-m membrane filter.…”

Section: Methodsmentioning

confidence: 99%

Genetic Improvement of Bacillus licheniformis Strains for Efficient Deproteinization of Shrimp Shells and Production of High-Molecular-Mass Chitin and Chitosan

Hoffmann

Daum

Köster

et al. 2010

Appl Environ Microbiol

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By targeted deletion of the polyglutamate operon (pga) in Bacillus licheniformis F11, a derivative form, F11.1 (⌬pga), was obtained that, along with lacking polyglutamate (PGA) formation, displayed enhanced proteolytic activities. The phenotypic properties were maintained in a strain in which the chiBA operon was additionally deleted: F11.4 (⌬chiBA ⌬pga). These genetically modified strains, carrying the ⌬pga deletion either alone (F11.1) or together with the ⌬chiBA (F11.4) deletion, were used in fermentations (20-liter scale) aiming at the deproteinization of shrimp shells in order to obtain long-chain chitin. After chemical deacetylation, the resulting chitosan samples were analyzed by nuclear magnetic resonance spectroscopy, size exclusion chromatography, and viscometry and compared to a chitosan preparation that was produced in parallel by chemical methods by a commercial chitosan supplier (GSRmbH). Though faint lipid impurities were present in the fermented polysaccharides, the viscosity of the material produced with the double-deletion mutant F11.4 (⌬pga ⌬chiBA) was higher than that of the chemically produced and commercially available samples (Cognis GmbH). Thus, enhanced proteolytic activities and a lack of chitinase activity render the double mutant F11.4 a powerful tool for the production of long-chain chitosan.Chitin {poly [␤-(134)-N-acetyl-D-glucosamine]}, a polysaccharide common to fungal cell walls and insect and crustacean carapaces, is-second only to cellulose-one of the most abundant natural polymers; it serves as the precursor of chitosan, a deacetylated derivative with numerous applications, e.g., in pharmaceuticals, cosmetics, and dairy products and in wastewater treatment, agriculture, and many other technological processes. Routinely, such applications require specific structural attributes, and the effectiveness and value of chitosan depend on its molecular weight and degree of deacetylation (21,27). Depending on the source and preparation, the physicochemical properties of chitin and chitosan may vary drastically (6); therefore, structural analysis of chitosan products is of the utmost importance.Procedures currently used to purify and transform chitin into chitosan (almost exclusively from shrimp shells) involve harsh chemical treatments accompanied by uncontrollable hydrolysis and chemical modifications, eventually resulting in the formation of undesired by-products such as irregularly deacetylated polymers (51). Since the removal of proteins and calcium carbonate by alternating acid and alkali treatments collaterally yields large amounts of aqueous waste, bioconversion is also desirable from the ecological point of view.As for the above-mentioned chemical procedures, biotechnological processes for chitin recovery follow the same rules of action (12); however, chemical demineralization and deproteinization approaches are replaced by fermentation steps using appropriate microorganisms. Due to the lack of harsh chemical agents, there is not only a considerable reduction of expenses for was...

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Chromatographie zur Bestimmung der Molmassen- und Teilchengrößenverteilung von Polymeren

Cited by 5 publications

References 11 publications

Cationic Starches as Substitute for Synthetic Cationic Flocculants in Solid−Liquid Separation of Harbor Sludge

Cationic Starches as Substitute for Synthetic Cationic Flocculants in Solid−Liquid Separation of Harbor Sludge

Das Verfahren zur Chitosan‐Gewinnung aus dem baltischen Krebs Gammarus lacustris

Genetic Improvement of Bacillus licheniformis Strains for Efficient Deproteinization of Shrimp Shells and Production of High-Molecular-Mass Chitin and Chitosan

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