Spectroscopic and Molecular Weight Studies of Polytoluidines

1989 ◽  
Vol 173 ◽  
Author(s):  
Y. Wei ◽  
K. F. Hsueh ◽  
S. Nagy ◽  
A. Ray ◽  
A. G. MacDiarmid ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Quantitative Estimation ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Oxidation States ◽  
H Nmr ◽  
Elution Pattern ◽  
Repeat Units ◽  
Base Form ◽  
Field Desorption Mass Spectrometry

ABSTRACTPoly(o-toluidine) and poly(m-toluidine) in base form have been characterized by infrared and lH NMR spectroscopy. Assignments of the proton NMR signals have been facilitated by the use of model compounds. The distinction between benzenoid and quinoid methyl resonances in the NMR permits a semi-quantitative estimation of the oxidation states of the polytoluidines. Infrared studies are consistent with a polyaniline-type backbone having pendant methyl groups. Field desorption mass spectrometry (FD-MS) was employed for estimation of the molecular weight of poly(o-toluidine). Gel-permeation chromatography of the same sample showed a bimodal elution pattern, suggesting that the FD-MS technique detects only the lower molecular weight fraction of the polymer. Despite this inherent limitation, FD-MS yields the interesting information that the polymer contains chains of both odd and even numbers of repeat units, necessitating the coexistence of different oxidation states in the base form of the polymer.

Determination of Free and Bound Cd, Zn, Cu, and Ag Ions in Lobster (Homarus americanus) Digestive Gland Extracts by Gel Chromatography Followed by Atomic Absorption Spectrophotometry and Polarography

1993 ◽  
Vol 76 (4) ◽  
pp. 794-798 ◽  
Author(s):  
Chiu L Chou ◽  
John F Uthe ◽  
Robert D Guy
Keyword(s):  
Molecular Weight ◽  
Metal Ions ◽  
Atomic Absorption ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Atomic Absorption Spectrophotometry ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Absorption Spectrophotometry ◽  
Gel Permeation

Abstract Gel-permeation chromatography followed by atomic absorption spectrophotometric and polarographic analyses were used to measure free and bound divalent metal ions in lobster digestive gland extracts prepared with or without oc-toluenesulfonyl fluoride, a protease inhibitor. Chromatography on Sephadex G-50 or G-100 yielded 3 UV-absorbing peaks, which corresponded, respectively, to the void volume, a medium molecular weight fraction, and a low molecular weight fraction that contained free divalent metal ions. In protease-inhibited extracts, only Zn+2 was found, whereas Cd, Cu, and Ag were bound in high and medium molecular weight fractions. Cd+2 and Zn+2 were rapidly released from their bound forms in the absence of a protease inhibitor, and their presence was confirmed by polarography with EDTA. Gel-permeation chromatography coupled with atomic absorption spectrophotometry offers a rapid method for following changes in the concentrations of bound and free metal ions during processing of shellfishbased foodstuffs.

Bioconjugation of papain with poly(N-vinylpyrrolidone): NMR characterization and study of its enzymatic activity

2021 ◽  
Vol 99 (1) ◽  
pp. 10-17
Author(s):  
L.E. Verduzco ◽  
Ana L. García-Pérez ◽  
Ramiro Guerrero-Santos ◽  
Antonio Ledezma-Pérez ◽  
Jorge Romero-García ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Chain Transfer ◽  
Gel Permeation Chromatography ◽  
Acid Group ◽  
H Nmr ◽  
Reversible Addition ◽  
Nmr Characterization ◽  
Vis Spectroscopy ◽  
C Nmr

A poly(vinylpyrrolidone) end-functionalized with a carboxylic acid group (PVP–CO2H) was synthesized by reversible addition-fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) polymerization mediated by 4-(O-ethylxanthyl)methyl benzoic acid. The molecular weight of the as-synthesized PVP–CO2H was estimated through UV–vis spectroscopy (Mn(UV–vis) = 7322 g/mol), gel permeation chromatography (GPC) (Mn(GPC) = 8670 g/mol), and 1H NMR, (Mn(NMR) = 8207 g/mol). The values obtained were close with the theoretical molecular weight (Mn(th) = 7925 g/mol). Subsequently, the preformed PVP–CO2H was activated to produce N-succinimidyl poly(vinylpyrrolidone) (PVP–NHS). This precursor was covalently coupled to papain to produce bioconjugate PVP–papain. The functional group modifications in the PVP chain-end were observed by the variations in the chemical shift values by 1H and 13C NMR and FTIR analysis at each step of the synthesis. The molecular weight of the PVP–papain was obtained by SEC–HPLC and suggests that, on average, four or five chains of PVP–CO2H were attached to one papain molecule. Compared with papain, the PVP–papain exhibited significantly improved catalytic activity, pH, and thermal stability. Additionally, the storage studies showed that the catalytic activity of PVP–papain was about 79% versus the native enzyme (29%), and this activity was maintained even when it was stored for 25 days.

Study of the fractional composition of wheat proteins and macaroni products during storage

2021 ◽  
pp. 776-783
Author(s):  
I.A. Tarasova ◽  
K.B. Gurieva ◽  
E.A. Tarasova ◽  
S.L. Beletskiy ◽  
N.A. Khaba
Keyword(s):  
Molecular Weight ◽  
Fractional Composition ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Protein Fractions ◽  
Low Molecular Weight ◽  
English Version ◽  
Wheat Proteins ◽  
Photometric Detection ◽  
Main Protein

The results of the molecular weight distribution of wheat proteins and macaroni products are presented. The fractional composition of proteins was determined by gel permeation chromatography on a Knauer Smartline chromatograph; preliminary hydrolysis was carried out using a thermostable bacterium α-Amylase, then it was centrifuged, filtered through a Teflon filter, and the size of protein molecules was determined by photometric detection at a wavelength of 280 nm. It has been shown that the main protein fraction in both wheat and macaroni products is a low molecular weight fraction up to 3 kD (up to 79.4% of all protein fractions). The fraction with low and medium molecular weight from 3 to 10 kD accounted for 2.7 to 48.2%, while the fraction with a molecular weight of more than 10 kD accounted for up to 15.2%. During storage, a redistribution of protein fractions and their enlargement were noted. English version of the article is available at URL: https://panor.ru/articles/study-of-the-fractional-composition-of-wheat-proteins-and-pasta-products-during-storage/74321.html

Study of the Carbohydrate Content of Mucus Glycoproteins from Normal and Diseased Colons

1981 ◽  
Vol 61 (2) ◽  
pp. 229-234 ◽  
Author(s):  
J. R. Clamp ◽  
G. Fraser ◽  
A. E. Read
Keyword(s):  
Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Carbohydrate Content ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Mucus Glycoprotein ◽  
Active Colitis ◽  
High Mannose ◽  
Mucus Glycoproteins

1. Mucus samples obtained from colectomy colons from 10 patients with ulcerative colitis and four patients with Crohn's disease of the colon, together with samples from 10 normal postmortem colons, have been studied. 2. Two glycoprotein fractions were isolated from mucosal scrapings by gel-permeation chromatography. The high-molecular-weight fraction consisted largely of mucus glycoproteins and was further purified to the glycopolypeptides. The low-molecular-weight fraction contained a glycoprotein with a high mannose content. The carbohydrate content of both the mucus glycoprotein and glycopolypeptide fractions were significantly reduced in active colitis. 3. Oligosaccharides were prepared from the mucus glycoprotein material. In the normal material more than half the units contained eight or more monosaccharide residues, whereas in the disease material the bulk of the units were smaller than this.

A New Green Process for Synthesising High Quality PLLA Materials

2013 ◽  
Vol 750-752 ◽  
pp. 1377-1380 ◽  
Author(s):  
Hui Li Shao ◽  
Xian Jue Zhou ◽  
Xue Chao Hu
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Green Process ◽  
Weight Average Molecular Weight ◽  
H Nmr ◽  
Ft Ir ◽  
C Nmr

Synthesis of Poly(L-lactide) (PLLA) by the ring-opening polymerization (ROP) of L-lactides in supercritical carbon dioxide (SC-CO2) with co-solvent were studied. Effects of kinds of co-solvent on the molecular weight (MW) and the molecular weight distribution (MWD) of the resultant polymers were investigated by the gel permeation chromatography (GPC). The resultant polymers were also characterized with1H NMR,13C NMR and FT-IR. It was found that PLLA with high purity and almost without racemization could be obtained by this technology and the acetone is the best co-solvent for this kind of polymerization. By using stannous octoate as initiator and acetone as co-solvent, PLLA having a weight-average molecular weight (Mw) near to 9×104and polydispersity index (PDI) of 1.7 was successfully synthesized.

scholarly journals Synthesis, Characterization and Copolymerization of N-(phenylamino)maleimide with MMA

2007 ◽  
Vol 4 (2) ◽  
pp. 265-271
Author(s):  
B. L. Hiran ◽  
S. N. Paliwal ◽  
Jyoti Choudhary ◽  
P. R. Choudhary
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Density Measurement ◽  
Gel Permeation Chromatography ◽  
Radical Copolymerization ◽  
Free Radical Copolymerization ◽  
H Nmr ◽  
Gel Permeation ◽  
Ft Ir ◽  
Thermal Stability Of

The free radical copolymerization of N-(phenylamino)maleimide (N-PAMI) was carried. The copolymerization with methyl methacrylate (MMA) was performed at 65°C with AIBN as the initiator in THF solvent. Resulting copolymer was characterized by density measurement, intrinsic viscosity, solubility, FT-IR &1H NMR spectroscopy. Effect of the solvent and time on copolymer yield was also investigated. The molecular weight of copolymer was determined by gel permeation chromatography (GPC). The thermal stability of copolymer was determined by Thermogravimetric analysis (TGA).

scholarly journals A feasible synthetic strategy for three-armed star poly(ester amine) via Michael addition polymerization

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Wei Yang ◽  
Cai-Yuan Pan
Keyword(s):  
Molecular Weight ◽  
Michael Addition ◽  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Glycol Diacrylate ◽  
H Nmr ◽  
Synthetic Strategy ◽  
Addition Polymerization ◽  
Feed Molar Ratio

AbstractThree-armed star-shaped poly(ester amine) was synthesized by Michael addition polymerizations of equal molar ratio of ethylene glycol diacrylate (EGDA) and piperazine (PZ) in the presence of a small amount of multifunctional monomer, 1,3,5-triacryloylhexa-hydro-1,3,5-triazine (TT) in CHCl3. When the polymerization proceeded almost completely, the molecular weight of the polymers formed were determined by the feed molar ratio of difunctional monomer to multifunctional monomer, and the molecular weight distribution (Mw/Mn) approached the theoretical value (Mw/Mn =1+1/f). The mechanism of the polymerization was investigated by 1H NMR and Gel permeation chromatography (GPC). The monomer concentration and the molar ratio of difunctional monomers/multifunctional monomer played an important role in the polymerization.

scholarly journals Preparation of novel amphoteric polyacrylamide and its synergistic retention with cationic polymers

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 162-170 ◽  
Author(s):  
Kaiji Yang ◽  
Jinghuan Chen ◽  
Qingjin Fu ◽  
Xuji Dun ◽  
Chunli Yao
Keyword(s):  
Molecular Weight ◽  
Chemical Structure ◽  
Guar Gum ◽  
Gel Permeation Chromatography ◽  
The Novel ◽  
Cationic Polymers ◽  
Cationic Starch ◽  
H Nmr ◽  
Gel Permeation ◽  
Scanning Electron

AbstractA novel amphoteric polyacrylamide (PDAA) was prepared by inverse emulsion polymerization. The influence of its cationic degree and molecular weight on retention property was discussed. Then, the chemical structure and micromorphology of the obtained PDAA were characterized by Fourier infrared spectrum (FTIR), NMR hydrogen spectrum (1H NMR), gel permeation chromatography (GPC), and scanning electron microscope (SEM). Finally, the synergistic retention effects of polydimethyldiallylammonium chloride (PDADMAC), cationic starch (CS), cationic guar gum (CHPG), cationic chitosan (CTS), and polyamine (PA) on the novel PDAA were investigated. The results showed that the optimum cationic degree and molecular weight of PDAA were 25% and 4 million, respectively. The chemical structure of PDAA was confirmed by FTIR, 1H NMR, and GPC. SEM showed that the particle size of PDAA was between 150 and 600 nm, and the particles were very stable because no broken particles were found. In addition, most of the five cationic polymers have good synergistic retention effect on PDAA, and the order of synergistic effect was PDAA/PDADMAC > PDAA/CTS > PDAA/CS > PDAA/CHPG > PDAA/PA.

scholarly journals Release of Protein-Bound N-ε -(γ -glutamyl)-Lysine during Simulated Gastrointestinal Digestion

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S153-S155 ◽  
Author(s):  
M. Hellwig ◽  
J. Löbner ◽  
A. Schneider ◽  
U. Schwarzenbolz ◽  
T. Henle
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Phenyl Isothiocyanate ◽  
High Molecular Weight Fraction ◽  
Gastrointestinal Digestion ◽  
Gamma Glutamyl ◽  
Simulated Gastrointestinal Digestion ◽  
Peptide Fraction

<I>N</I>-&epsilon; -(&gamma; -glutamyl)-lysine is a crosslinking amino acid formed in food mainly during treatment with microbial transglutaminase (mTG). The purpose of this study was to investigate to which amount isopeptides are detectable in a low-molecular weight peptide fraction after simulated gastrointestinal digestion. Casein, which had been enriched with <I>N</I>-&epsilon; -(&gamma;-glutamyl)-lysine by mTG to different extents, was subjected to simulated gastrointestinal digestion and the resulting peptide mixture fractionated into a low- and a high molecular weight fraction (below or above 200–500 Da, respectively) using semipreparative gel permeation chromatography. <I>N</I>-&epsilon; -(&gamma;-glutamyl)-lysine was analysed in these fractions by RP-HPLC after enzymatic hydrolysis and derivatisation with phenyl isothiocyanate. <I>N</I>-&epsilon; -(&gamma;-glutamyl)-lysine was found nearly exclusively in the high-molecular weight fraction, indicating that dietary <I>N</I>-&epsilon; -(&gamma;-glutamyl)-lysine present in mTG-modified food proteins is not available for absorption in the intestine.

Synthesis and Characterization of a Novel Biodegradable Polymer with Fluorescence Property

2011 ◽  
Vol 197-198 ◽  
pp. 21-26
Author(s):  
Ji Hang Li ◽  
Dong Jian Shi ◽  
Na Hu ◽  
Wei Fu Dong ◽  
Jun Feng Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Fluorescence Property ◽  
H Nmr ◽  
Gel Permeation ◽  
Fluorescent Polymer ◽  
Poor Solvent

In this paper, a novel biodegradable and fluorescent polymer: fluorescein-polylactide (FL-PLA) was synthesized by FL and lactide in the method of ring-opening polymerization with the catalysis of Sn(Oct)2under 130°C . The structure and molecular weight of FL-PLA were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H-NMR) spectroscopy, and gel permeation chromatography (GPC). The molecular weight of FL-PLA increased from 9.03×103to 21.24×103with decreasing the amount of FL and kept a narrow distribution. The result of differential scanning calorimeter (DSC) showed that Tgincreased from 52 to 72°C with increasing the molecular weight of polymer. Moreover, the average number content of FL in each molecular chain decreased from 0.96 to 0.81 with decrement of the amount of FL. Furthermore, FL-PLA showed the fluorescence property, and the fluorescence intensity could be controlled by the amount of FL. The FL-PLA nanoparticles were prepared by mixing the good and poor solvent, and the diameter was about 3 μm with regular spherical morphology.

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