Fractionation of Methyl Cellulose According to Polarity – a Tool to Differentiate First and Second Order Heterogeneity of the Substituent Distribution

2006 ◽  
Vol 207 (11) ◽  
pp. 954-965 ◽  
Author(s):  
Roland Adden ◽  
Romy Müller ◽  
Petra Mischnick
Keyword(s):  
Methyl Cellulose ◽  
Second Order ◽  
Substituent Distribution

scholarly journals Analysis of the Heterogeneities of First and Second Order of Cellulose Derivatives: A Complex Challenge

2021 ◽  
Vol 2 (4) ◽  
pp. 843-865
Author(s):  
Petra Mischnick ◽  
Kristin Voiges ◽  
Julia Cuers-Dammann ◽  
Inga Unterieser ◽  
Patrick Sudwischer ◽  
...  
Keyword(s):  
Methyl Cellulose ◽  
Normal Phase ◽  
Second Order ◽  
Cellulose Derivatives ◽  
Cellulose Ethers ◽  
Substituent Distribution ◽  
Analytical Work ◽  
Polysaccharide Derivatives ◽  
Analytical Approaches

The complexity of the substituent distribution in polysaccharide derivatives is discussed and defined. The challenges regarding analytical characterization that results from various interrelated categories of distributions, including molecular weight, chemical composition, and microstructure, are outlined. Due to these convoluted levels of complexity, results should always be interpreted with carefulness. Various analytical approaches which have been applied to starch and cellulose derivatives are recapped, including enzymatic, mass spectrometric, and chromatographic methods. The relation of heterogeneities of first and second order among and along the polysaccharide chains is addressed. Finally, examples of own analytical work on cellulose ethers are presented, including the MS analysis of methyl cellulose (MC) blends and fractionation studies of fully esterified MC, especially its 4-methoxybenzoates by gradient HPLC on normal phase. Preparative fractionation according to the degree of substitution (DS) allows follow-up analysis in order to get more detailed information on the substituent distribution in such sub-fractions.

Substituent Distribution and Clouding Behavior of Hydroxypropyl Methyl Cellulose Analyzed Using Enzymatic Degradation

2006 ◽  
Vol 7 (12) ◽  
pp. 3474-3481 ◽  
Author(s):  
Herje Schagerlöf ◽  
Marika Johansson ◽  
Sara Richardson ◽  
Gunnar Brinkmalm ◽  
Bengt Wittgren ◽  
...  
Keyword(s):  
Enzymatic Degradation ◽  
Methyl Cellulose ◽  
Substituent Distribution ◽  
Hydroxypropyl Methyl Cellulose

scholarly journals Carboxyl Methyl Cellulose@Guar Gum@ CuO Nanoparticle as Effective Adsorbent for the Removal of Dye From Aqueous Solution

2021 ◽  
Author(s):  
Ali Hosseinian Naeini ◽  
mohammad Reza kalaee ◽  
Omid Moradi ◽  
Ramin Khajavi ◽  
Majid Abdouss
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Guar Gum ◽  
Methyl Cellulose ◽  
Second Order ◽  
Order Kinetic ◽  
Adsorbent Surface ◽  
Bet Analysis ◽  
Influential Parameters ◽  
Carboxy Methyl

Abstract In the present study, the study and fabrication of inorganic organic nanocomposites with Guar gam and Carboxy methyl cellulose biopolymer substrates. The synthesis nanocomposite of CMC/GG/CuO-3 is biodegradable and biocompatible, and also has a significant efficiency in removing malachite green (MG) dye from aqueous solution. Properties were evaluated by XRD, FTIR, SEM, EDX and BET analysis. Important and influential parameters on the adsorption process such as adsorbent amount, initial dye concentration, pH and contact time on the removal efficiency of contaminants from aqueous solutions were investigated. Maximum removal efficiency and adsorption capacity were 92.4% and 18.6 mg/g, respectively. In order to analyze the mechanism of experimental data, two First-order and Second-order kinetic models were used, which followed the second-order kinetics with R2=1. Also, the study of Freundlich and Langmuir isotherms showed that the isotherm model of Freundlich follows the R2=0.94, which indicates the non-uniformity of adsorption on the adsorbent surface.

Critical re-investigation of the alditol acetate method for analysis of substituent distribution in methyl cellulose

Cellulose ◽  
2012 ◽  
Vol 19 (3) ◽  
pp. 993-1004 ◽  
Author(s):  
Kristin Voiges ◽  
Roland Adden ◽  
Marian Rinken ◽  
Petra Mischnick
Keyword(s):  
Methyl Cellulose ◽  
Substituent Distribution ◽  
Alditol Acetate

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Disappearance Voltage Determinations Using a Convergent Beam

1971 ◽  
Vol 29 ◽  
pp. 184-185
Author(s):  
W. L. Bell
Keyword(s):  
Second Order ◽  
Objective Method ◽  
Uniform Thickness ◽  
Rocking Curve ◽  
Crystal Perfection ◽  
Kikuchi Line ◽  
Central Maximum ◽  
Diffraction Patterns ◽  
Convergent Beam ◽  
Beam Technique

Disappearance voltages for second order reflections can be determined experimentally in a variety of ways. The more subjective methods, such as Kikuchi line disappearance and bend contour imaging, involve comparing a series of diffraction patterns or micrographs taken at intervals throughout the disappearance range and selecting that voltage which gives the strongest disappearance effect. The estimated accuracies of these methods are both to within 10 kV, or about 2-4%, of the true disappearance voltage, which is quite sufficient for using these voltages in further calculations. However, it is the necessity of determining this information by comparisons of exposed plates rather than while operating the microscope that detracts from the immediate usefulness of these methods if there is reason to perform experiments at an unknown disappearance voltage.The convergent beam technique for determining the disappearance voltage has been found to be a highly objective method when it is applicable, i.e. when reasonable crystal perfection exists and an area of uniform thickness can be found. The criterion for determining this voltage is that the central maximum disappear from the rocking curve for the second order spot.

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