Enzymic Method for Determination of Glycerol: Chain Lengths of Hexans

1980 ◽  
pp. 73-76
Author(s):  
R.J. STURGEON
Keyword(s):  
Chain Lengths

Effectivity of dolichyl phosphates with different chain lengths as acceptors of nucleotide activated sugars

1986 ◽  
Vol 6 (7) ◽  
pp. 677-683 ◽  
Author(s):  
P. Löw ◽  
E. Peterson ◽  
M. Mizuno ◽  
T. Takigawa ◽  
T. Chojnacki ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Animal Tissues ◽  
Physiological Importance ◽  
Chain Lengths

Chemical synthesis of different S-forms of dolichyl-P was performed in order to investigate the use of these polyprenes in mannosyl, glucosyl and glucosaminyl transferase reactions. Determination of the Vmax values for a series of dolichyl-P demonstrated that the velocities of transferase reactions with all those dolichyl-P derivatives present in animal tissues are largely the same. The apparent Km values for the various dolichyl-P in the transferase system studied differed, but this property does not appear to have physiological importance.

Determination of Hg2+ Ions Using Electrodes Modified with Dithia-Podands Having Different End Alkyl Chain Lengths

2001 ◽  
Vol 13 (12) ◽  
pp. 1003-1007 ◽  
Author(s):  
Mi-Sook Won ◽  
Yun-Jung Bae ◽  
Shim-Sung Lee ◽  
Yoon-Bo Shim
Keyword(s):  
Alkyl Chain ◽  
Chain Lengths

Identification of fatty acids from butterfat using a combined gas chromatograph-mass spectrometer

1967 ◽  
Vol 34 (2) ◽  
pp. 115-121 ◽  
Author(s):  
Ragnar Ryhage
Keyword(s):  
Fatty Acids ◽  
Mass Spectrometer ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Straight Chain ◽  
Molecular Weights ◽  
Acid Methyl ◽  
Branched Chain ◽  
Chain Lengths

SummaryThe identification and approximate quantitative determination of methyl esters of fatty acids from commercial butterfat was obtained with a combined gaschromatograph-mass spectrometer instrument. Fifty-two components, straight chain saturated and unsaturated, as well as branched chain compounds, were identified. Seven monomethyl saturated fatty acid methyl ester isomers were identified for both C15 and C17, i.e. with chain lengths of 14 and 16 carbon atoms, respectively. Multibranched fatty acids with molecular weights of 326 and 368 were found. The results were obtained in one day.

Safety Assessment of Methyl Glucose Polyethers and Esters as Used in Cosmetics

2016 ◽  
Vol 35 (2_suppl) ◽  
pp. 12S-40S
Author(s):  
Wilbur Johnson ◽  
Bart Heldreth ◽  
Wilma F. Bergfeld ◽  
Donald V. Belsito ◽  
Ronald A. Hill ◽  
...  
Keyword(s):  
Safety Assessment ◽  
Systemic Exposure ◽  
Molecular Structures ◽  
Entire Group ◽  
Molecular Weights ◽  
Toxicological Data ◽  
Data Gaps ◽  
Cosmetic Formulations ◽  
Chain Lengths

The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of methyl glucose polyethers and esters which function in cosmetics as skin/hair-conditioning agents, surfactants, or viscosity increasing agents. The esters included in this assessment are mono-, di-, or tricarboxyester substituted methyl glucosides, and the polyethers are mixtures of various chain lengths. The Panel reviewed available animal and clinical data, including the molecular weights, log Kows, and other properties in making its determination of safety on these ingredients. Where there were data gaps, similarities between molecular structures, physicochemical and biological characteristics, and functions and concentrations in cosmetics allowed for extrapolation of the available toxicological data to assess the safety of the entire group. The Panel concluded that there likely would be no significant systemic exposure from cosmetic use of these ingredients, and that these ingredients are safe in cosmetic formulations in the present practices of use and concentration.

scholarly journals Comparison of Three Methods to Determine the Degree of Substitution of Quinoa and Rice Starch Acetates, Propionates, and Butyrates: Direct Stoichiometry, FTIR, and 1H-NMR

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 83 ◽  
Author(s):  
Nabilah Abdul Hadi ◽  
Berthold Wiege ◽  
Sebastian Stabenau ◽  
Ali Marefati ◽  
Marilyn Rayner
Keyword(s):  
1H Nmr ◽  
Conformational Changes ◽  
Direct Determination ◽  
Reference Method ◽  
Degree Of Substitution ◽  
Proton Nuclear Magnetic Resonance ◽  
Rice Starch ◽  
Acid Anhydrides ◽  
Chain Lengths

Rice and quinoa starch esters were prepared by acylation using short-chain fatty acid anhydrides with different chain lengths (acetic, propionic, and butyric anhydride). A direct stoichiometric method based on the acylation reaction was used to determine the degree of substitution (DS) and acyl content (AC). In addition, Fourier-transform infrared spectroscopy (FTIR) was used to validate the conformational changes of acylated starch and 1H-NMR was used as a DS reference method. DS by stoichiometric calculation was shown to be in agreement with FTIR and was comparable with DS obtained from Proton nuclear magnetic resonance (1H-NMR). Based on this study, stoichiometric calculation allows rapid and direct determination of substitution levels and acyl content without the loss of samples, which provides efficiency and optimization of manufacturing procedures in producing the desired level of esterified starches.

scholarly journals Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1782 ◽  
Author(s):  
Alojz Anžlovar ◽  
Matjaž Kunaver ◽  
Andraž Krajnc ◽  
Ema Žagar
Keyword(s):  
Cellulose Nanocrystals ◽  
Melt Processing ◽  
Side Chain ◽  
Critical Percolation ◽  
Reinforcement Effect ◽  
Poly Ethylene ◽  
Average Size ◽  
Surface Modified ◽  
Chain Lengths

Cellulose nanocrystals (CNCs) were surface modified by esterification in tetrahydrofuran (THF) at 25 °C using different catalysts and anhydrides bearing different alkyl side chain lengths. Unmodified and acetic anhydride (AcAnh)-modified CNCs were studied as potential nanofillers for linear low-density poly(ethylene) (LLDPE). Nanocomposites were prepared by melt processing. Determination of the size and size distribution of CNCs in the nanocomposites by SEM revealed an enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, since the average size of the aggregates of the modified CNCs (0.5–5 μm) was smaller compared to that of the unmodified CNCs (2–20 μm). Tensile test experiments revealed an increase in the nanocomposites’ stiffness and strain at break—by 20% and up to 90%, respectively—at the CNC concentration of 5 wt %, which is close to the critical percolation concentration. Since the CNC nanofiller simultaneously reduced LLDPE crystallinity, the reinforcement effect of CNCs was hampered. Therefore, the molding temperature was increased to 120 °C, and, in this way, the greatest increase of the Young’s modulus was achieved (by ~45%). Despite the enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, no additional effect on the mechanical properties of the nanocomposites was observed in comparison to the unmodified CNC.

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