Rapid method for the determination of the substitution pattern of O-methylated 1,4-glucans by high-pH anion-exchange chromatography with pulsed amperometric detection

Heinrich, Jürgen; Mischnick, Petra

doi:10.1016/0021-9673(96)00468-2

Cited by 27 publications

(15 citation statements)

References 10 publications

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“…[18] However, calibration with maltose and 2,3,6-tri-O-methyl-D-glucose showed a relative sensitivity of 7:1 in favour of the unprotected sugar. Obviously, O-methylation strongly influences the reducing power of the glucose, which is well known for electrochemical oxidation, [19] but might also be influenced by the poorer solubility of a permethylated compound in the aqueous reaction system (results not shown). Alternatively, the amount of non-reducing terminal glucosyl units was determined after 4-O-ethylation (if not already), methanolysis and acetylation by GLC.…”

Section: Characterisation Of the Productsmentioning

confidence: 99%

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Novel Possibilities by Cationic Ring‐Opening Polymerisation of Cyclodextrin Derivatives: Preparation of a Copolymer Bearing Block‐Like Sequences of Tri‐O‐methylglucosyl Units

Adden

Bösch

Mischnick

2004

Macro Chemistry & Physics

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Summary: Equimolar mixtures of O‐permethylated and O‐perdeuteromethylated cyclodextrins were submitted to cationic ring‐opening polymerisation (CROP) with Et3OPF6 or BF3 · Et2O as initiator in dichloromethane. Reaction started after an incubation time and yielded a polymeric product, which was partially degraded again during competing chain transfer reaction. Average block length was determined by ESI‐MS after partial methanolysis and was found to be close to the theoretical value of 14 for β‐cyclodextrin in the early stage of the reaction, but decreased to 2–5 during further chain transfer reactions accompanied by an equilibration of α‐ and β‐configurated glucosidic linkages to a ratio of 64:36. Molecular weight was estimated from end group analysis and GPC to reach about 29 000 as a maximum. From 31P NMR spectra of the initiator it was obvious that PF is partly hydrolysed to PO2F under participation of the glass surface. magnified image

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Section: Characterisation Of the Productsmentioning

confidence: 99%

“…The high tendency to chain transfer reactions indicates that no CD ring strain is required to start the reaction. The reaction mechanism will be further studied by using reaction vessels with inert surfaces and additonal 11 B, 19 F, 31 P NMRexperiments.…”

Section: Reaction Mechanismmentioning

confidence: 99%

Novel Possibilities by Cationic Ring‐Opening Polymerisation of Cyclodextrin Derivatives: Preparation of a Copolymer Bearing Block‐Like Sequences of Tri‐O‐methylglucosyl Units

Adden

Bösch

Mischnick

2004

Macro Chemistry & Physics

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“…[25] Also water soluble O-methyl glucoses can be separated due to the acidity of free sugar OH groups. [26] A drawback is the strong decrease of the response in the electrochemical detector with increasing DS of the glucose derivatives and the significant differences for the monoand disubstituted regioisomers that requires complete resolution for any quantitative evaluation. In addition response factors vary with the stage of the electrode.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

“…The eight constituents of methylcelluloses or starches can be separated by HPAEC-PAD [26] (no differentiation of anomers) or reduced and acetylated to yield partially methylated glucitol acetates which can be analyzed by GLC-FID and GLC-MS. After reductive amination with p-aminobenzonitrile or another appropriate amine these compounds can be separated by capillary electrophoresis in a borate buffer. [34] With increasing number of methylene groups aqueous acid hydrolysis becomes less appropriate.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Structure analysis of 1,4-glucan derivatives

Mischnick

Heinrich

Gohdes

et al. 2000

Macromol. Chem. Phys.

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Cellulose, starch and cyclodextrin ethers and esters are produced for many fields of application as for example oil recovery, building and ceramic materials, textile and paper industry, food, cosmetics, and pharmaceuticals. For further development of new types of derivatives and also for a better understanding of their properties a detailed analysis of the usually complex mixtures is required. By complete degradation, separation and quantification of appropriate monomer derivatives the regioselectivity in the glucose unit can be determined. For the determination of the substitution pattern in the polymer chain partial random degradation, oligomer analysis by mass spectrometry, and subsequent statistical evaluation can be applied. The composition of products obtained by enzymatic degradation also reflects the pattern in the polymer chain. In addition a possible heterogeneity of the material must be taken into consideration, since any degradation averages the structural information.

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“…NMR spectroscopy, [1] electrospray ionizationmass spectrometry (ESI-MS), [2] chromatographic [3][4][5][6][7] and electrophoretic [8] separation of appropriate monomer derivatives have been applied successfully. Analysis of the substituent distribution along the polymer chain is very challenging.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Analysis of the Substituent Distribution in Hydroxyethyl Celluloses by Quantitative MALDI‐ToF‐MS

Adden

Müller

Brinkmalm

et al. 2006

Macromolecular Bioscience

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Three HECs with a high MS (HEC 1: 1.89, HEC 2: 1.94, HEC 3: 3.03) were analyzed with respect to their substituent distribution and tandem reaction in the glucosyl unit by GLC of the corresponding glucitol acetates, and along the polymer chain by MALDI-ToF-MS after a multi-step sample preparation. For comparison of the experimental data with a random pattern an extended Bernoulli plot was applied to calculate a random distribution for the composition of un-, mono-, di-, tri-, and up to heptasubstituted glucosyl units (c0, c1, c2, ... c7).

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Rapid method for the determination of the substitution pattern of O-methylated 1,4-glucans by high-pH anion-exchange chromatography with pulsed amperometric detection

Cited by 27 publications

References 10 publications

Novel Possibilities by Cationic Ring‐Opening Polymerisation of Cyclodextrin Derivatives: Preparation of a Copolymer Bearing Block‐Like Sequences of Tri‐O‐methylglucosyl Units

Novel Possibilities by Cationic Ring‐Opening Polymerisation of Cyclodextrin Derivatives: Preparation of a Copolymer Bearing Block‐Like Sequences of Tri‐O‐methylglucosyl Units

Structure analysis of 1,4-glucan derivatives

Comprehensive Analysis of the Substituent Distribution in Hydroxyethyl Celluloses by Quantitative MALDI‐ToF‐MS

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