Gelchromatographie

Heitz, Walter

doi:10.1002/ange.19700821702

“…The analysis of epoxy resins is complicated by the fact, that in addition to molar mass distribution (MMD) a functionality type distribution (FTD) and a topological distribution (linear vs. branched molecules) is encountered. The analysis of MMD using size exclusion chromatography (SEC) by modelling the individual stages of the synthesis and describing the polymerization kinetics has been discussed in a number of papers [7][8][9][10] . However, in these works FTD has not been considered.…”

Section: Introductionmentioning

confidence: 99%

New analytical methods for epoxy resins, 1. Liquid chromatography at the critical point of adsorption and MALDI-TOF mass spectrometry

Adrian

¹

,

Braun

²

,

Rode

³

et al. 1999

Angew. Makromol. Chem.

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The analysis of bisphenol A based epoxy resins by size exclusion chromatography, liquid chromatography at the critical point of adsorption and MALDI‐TOF mass spectrometry with respect to molar mass, functionality, and branching is described. For obtaining proper molar masses, size exclusion chromatography must be calibrated by a combined calibration curve based on polystyrene and epoxy resin oligomers. Liquid chromatography at the critical point of adsorption yields quantitative data on different functionality fractions, including fully epoxydized, glycidyl‐diol and bisdiol oligomers. The different functionality fractions can be efficiently identified by MALDI‐TOF mass spectrometry. In addition, these measurements yield information on the number of branching points per oligomer molecule.

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“…The liberated 4-nitroaniline was measured photometrically at 405 nm. The volume of the swollen gel was obtained by subtracting the void volume (37%) from the volume of the settled gel [7] Substrate gel Ligand concentration pmol/ml swollen gel P-EAhx-Phe-Nan 2.48 P-(EAhx)z-Phe-Nan 22.00 NH4CI, 1 M NH3 buffer, pH 8.8, at 0°C for 5 h. The gel was washed with water/dimethylsulfoxide ( l / l , v/v) and 0.1 M acetate buffer, 1 M NaCI, pH 4.0, until no 4-nitroaniline could be detected in the washings. The pH of the gel suspension was adjusted to 4.0 and the suspension was stored at 4°C.…”

Section: Synthesis Of Polyacrylamide-bound Substratesmentioning

confidence: 99%

“…The liberated 4-nitroaniline was measured photometrically at 405 nm. The volume of the swollen gel was obtained by subtracting the void volume (37%) from the volume of the settled gel [7] Substrate gel Ligand concentration pmol/ml swollen gel P-EAhx-Phe-Nan 2.48 P-(EAhx)z-Phe-Nan 22.00 NH4CI, 1 M NH3 buffer, pH 8.8, at 0°C for 5 h.…”

Section: Synthesis Of Polyacrylamide-bound Substratesmentioning

confidence: 99%

Enzymatic Attack on Immobilized Substrates

Fischer

¹

,

Lange

²

,

Jakubke

³

1978

European Journal of Biochemistry

6

0

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1. The chyrnotrypsin-catalyzed hydrolysis of polyacrylamide-bound L-phenylalanine 4-nitroanilide was studied. As a spacer, one or two 6-aminohexanoyl residues were inserted between the matrix and ligand.2. In the course of the enzymatic hydrolysis of polyacrylamide-bound substrates, enzyme adsorption by the gel substrates was observed. A quasi equilibrium of enzyme partitioning was reached after approximately 20-min incubation time. The enzyme adsorption could be described by the Langmuir adsorption isotherm.3. The substrates attached via spacers to the matrix were completely hydrolyzed. 4. The initial course of the product vs time curves, as well as the dependence of the initial hydrolysis rates on enzyme concentration or substrate concentration, have been interpreted by the Nernst reaction theory. From the results obtained it has been concluded that the initial rate of the hydrolysis of polyacrylamide-bound L-phenylalanine 4-nitroanilide depends on the velocity of enzyme diffusion into the matrix.Results obtained with agarose-bound L-phenylalanine 4-nitroanilide show that the diffusion of the enzyme into the substrate gel does not influence the chymotrypsin-catalyzed hydrolysis to a significant degree. On the other hand, only a definite part of the bound ligand, dependent on the spacer length, is accessible to enzymatic attack [l]. This behaviour is presumably due to the structure of agarose [ 2 , 3 ] . The gross conformation of most synthetic polymers may be described by the model of random coil [4]. In comparison with agarose gels, synthetic crosslinked gels contain, on an average, smaller pores and a more flexible matrix. These parameters of synthetic gels depend on the degree of cross-linking.In the present paper we have tried to study the influence of a matrix different from agarose on the enzymatic hydrolysis of immobilized low-molecularweight substrates. For this purpose polyacrylamide (Biogel P100) was chosen. In polyacrylamide the interactions of the polymeric chains should be restricted to hydrogen bonds between the carboxyl amide groups Abbreviations. EAhx-Phe-Nan, 6-aminohexanoyl-~-phenylalanine 4-nitroanilide ; (EAhx)2-Phe-Nan, 6-aminohexanoyl-6-aminohexanoyl-L-phenylalanine 4-nitroanilide; P-, polyacrylamidebound; A-, agarose-bound; PhMeS03-, phenylmethanesulfonyl-.Enzyme. Chymotrypsin (EC 3.4.21.1).if cross-linking is neglected. As in our studies with agarose-bound substrates 111, L-phenylalanine 4-nitroanilide interposed by either one to two 6-aminohexanoyl residues was bound to polyacrylamide and used for the investigation of both the behaviour of protein adsorption and enzymatic hydrolysis. MATERIALS AND METHODS MaterialsBiogel PI00 was purchased from Bio-Rad Laboratories and crystalline chymotrypsin was purchased from Spofa (Prague). All other reagents were the purest commercially available. Synthesis of Polyacrylamide-Bound SubstratesBiogel P100, containing azide groups, was prepared according to Inman and Dintzis [5]. The ligands were coupled to the matrix in 0.2 M carbonate buffer/dimethy...

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Plastics, Analysis

Elgert

¹

2000

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Polymer Isolation 3. Preliminary Tests for Polymer Identification 4. Chemical Analysis 4.1. Heteroelements and Functional Groups 4.2. Separation and Identification Schemes 4.3. Spectroscopic Methods 5. Molecular Mass Determination 5.1. Absolute Methods 5.1.1. Membrane Osmometry 5.1.2. Lowering of Vapor Pressure 5.1.3. Ultracentrifugation 5.1.4. Light Scattering 5.2. Relative Methods 5.3. Determination of Molecular Mass Distribution 6. Determination of Sequential Structure 6.1. NMR Spectroscopy 6.2. Pyrolysis Gas Chromatography 7. Determination of Chemical Heterogeneity

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Gelchromatographie

Cited by 36 publications

References 99 publications

New analytical methods for epoxy resins, 1. Liquid chromatography at the critical point of adsorption and MALDI-TOF mass spectrometry

New analytical methods for epoxy resins, 1. Liquid chromatography at the critical point of adsorption and MALDI-TOF mass spectrometry

Enzymatic Attack on Immobilized Substrates

Plastics, Analysis

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