Determination Of Average Molecular Weight Research Articles

Rapid and simple determination of average molecular weight and composition of synthetic polymers via electrospray ionization-mass spectrometry and a Bayesian universal charge deconvolution.

Simple, affordable, and rapid methods for identifying the molecular weight (MW) distribution and macromolecular composition of polymeric materials are limited. Current tools require extensive solvent consumption, linear calibrations, and expensive consumables. A simple method for the determination of average MW (Mn , Mw ) and chain end groups is demonstrated for synthetic homopolymer standards using direct injection electrospray ionization-mass spectrometry (ESI-MS) and an open-sourced charge deconvolution (CDC) algorithm. Five homopolymer standards in the 1-7kDa MW range were analyzed using direct-injection ESI-MS on a quadrupole/time-of-flight mass spectrometer. The samples investigated, viz. two poly(ethylene oxide) (PEO) and two poly(styrene sulfonic acid) (PSS) standards with narrow polydispersity and one poly(d,l-alanine) (pAla) standard with undefined polydispersity, were chosen to illustrate challenges with ESI-MS quantitation. Using the UniDec program, weight average MWs (Mw ) obtained from the charge-deconvoluted spectra were compared to the reported Mw data of the standards from size exclusion chromatography (SEC) measurements. The MW data derived for the PSS, PEO, and pAla standards agreed well with the corresponding reported Mw or MW range values. The method was able to provide MW, degree of polymerization (DP), and polydispersity index (PDI) information for polymers with narrow (PSS, PEO) as well as broader (pAla) molecular weight distribution; this feature provides an advantage over MW analysis via matrix-assisted laser desorption/ionization (MALDI) for ESI-compatible materials. PSS standards differing in average MW by only a few repeat units could be confidently distinguished. Additionally, the oligomeric resolution observed for all samples studied unveiled chain-end information not available through chromatographic analysis. Overall, the free and easy-to-use UniDec CDC algorithm provides a simple, alternative method to measuring MW and DP for polymeric materials without high solvent consumption, expensive ionization sources, or calibration curves. Information about the masses of individual oligomers and the possibility to further characterize these oligomers using tandem mass spectrometry and/or ion mobility techniques constitutes additional benefits of this approach vis-à-vis traditional MW and PDI elucidation through SEC.

End Group Analysis of Polyisobutylene Succinic Anhydride (PIBSA) Carried Out with Pyrene Excimer Fluorescence

A procedure is established to determine the molar fraction (fdoubly) of doubly-maleated polyisobutylene (PIBSA2) in a PIBSA sample mainly constituted of mono-maleated polyisobutylene (PIBSA1), where the succinic anhydride (SA) groups are located at the end of the PIB chain. To this end, a PIBSA sample was labeled with 1-pyrenemethylamine (PyMA) to generate PIB-PySI, where the 1-pyrenemethyl group was linked to the PIB chain via a succinimide group. Depending on the procedure applied to purify the PIB-PySI samples, different regions of the molecular weight distribution (MWD) representing the PIBSA samples could be isolated and characterized by a combination of GPC, FTIR, and UV–vis absorption analysis to yield its MWD, number of isobutylene units per succinic anhydride (NIB/NSA), and pyrene content (λPy, in μmol of pyrene per gram of sample). These analyses were consistent with the expected size and chemical composition of the different PIB-PySI samples. fdoubly was calculated from the molar fraction (fagg) of pyrene labels attached onto the PIBSA2 species. fagg was determined through the global model free analysis (MFA) of the fluorescence decays of the pyrene monomer and excimer acquired for solutions of the PIB-PySI samples in THF. The different fractions of the MWD of the PIBSA sample yielded similar fdoubly values across the MWD, implying an even distribution of PIBSA2 species across a PIBSA MWD. The constancy of fdoubly across the MWD enabled the determination of the number average molecular weight (Mn) of the PIB-PySI samples from λPy. An analysis combining the GPC traces obtained with a differential refractive index and UV–vis absorption detector yielded the MWD of the original PIBSA sample. These experiments demonstrated that the proposed PEF-based methodology can be applied to characterize the SA end groups of PIBSA samples and could be further extended to characterize the end groups of other end-functionalized polymers.

Experimental studies on static laser light scattering of synthetized poly (acrylonitrile-co- methyl methacrylate) copolymer at room temperature

The static light scattering technique (SLS) is one of the absolute techniques that are used for the determination of weight average molecular weight (M¯w) of polymer solutions. In this technique, the scattered laser light intensity is measured at different scattering angles for various polymer concentrations to construct the Zimm plot which can be used for a simultaneous determination of M¯w, radius of gyration (Rg), and the second virial coefficient (A2). In this study, Poly (acrylonitrile–co-methyl methacrylate) copolymer, P(AN-co-MAA), was synthesized from acrylonitrile (AN) and methyl methacrylate (MMA) monomers using the precipitation polymerization method. Polymerization was carried out using potassium persulfate (K2S2O8) as an initiator with monomer ratios 1:1 of AN: MMA. The co-polymerization process was verified by Fourier transform infrared spectroscopy (FTIR). Refractive index (n) and refractive index increment (dn/dc) of the P(AN-co-MAA) copolymer solutions were determined experimentally using a Mach-Zehnder interferometer excited by a low power He-Ne laser in order to calculate the M¯w, Rg, and A2 of the synthetized copolymer using the static laser light scattering technique. M¯w, Rg, and A2 were found to be 9.7 × 105 g/mol, 345 nm, and 5 × 10−7 mol. cm3/g2.

Cordial physico-chemical characteristics of some trimethylolpropane triesters as base synthetic lubricant for turbo- jet aircrafts

The use of synthetic ester oils is presently an absolute necessity. Polyols ester type is the preferable synthetic lubricant to meet the demands of the lightweight gas turbine engine that used in civilian and military air crafts overcoming the lack ability of mineral lubricants. In this work, trimethylolpropanetributyrate, triheptanoate and trinonanoate esters were prepared using Dean Stark apparatus under specified optimum conditions verifying a conversion of 96.8–98.5% within 5.3–6.3 h. The esters were characterized by; i.r., elementary and average mean molecular weight determination, density, viscosity…etc. Some of their cordial properties were correlated to their chain length and some correlations were deduced. Comparison of these properties with the French Air specification 3514 (Nato 0–150) and those for the commercial turbonycoil 13B which is used for French aircrafts indicates that, some of the prepared esters are suitable as base turbine oils. These synthetic base oils may be blended with addition of the appropriate additives to produce final turbine oil for air crafts of speed regime coming towards supersonic.

NaOH induced the complete dissolution of ι-carrageenan and the corresponding mechanism

In the present research, the complete dissolution of carrageenan was realized by using NaOH aqueous solution and the corresponding mechanism was successfully revealed. The properties of carrageenan solution prepared in NaOH aqueous solution were comprehensively studied by gel temperature, differential scanning calorimetry and dynamic light scattering. The intra- and intermolecular interactions of carrageenan in NaOH/H2O system were studied by a combination of NMR measurements (including 13C NMR and 23Na NMR) and FTIR. The stability of carrageenan in NaOH aqueous solution was studied by the average molecular weight and viscosity determination. The results indicated that gel temperature and gel-sol transition temperature of carrageenan solution decrease with the dosage increasing of NaOH and a true and stable carrageenan solution was obtained by completely dissolving carrageenan in NaOH aqueous solution. The dissolution mechanism was that carrageenan chains were surrounded directly by NaOH hydrates to form hydrogen-bonded structure, leading to the good dissolution.

Determination of average molecular weight of guar gum by a simple twice headspace extraction gas chromatographic technique

This paper proposed a new method for the determination of the viscosity average molar mass of guar gum, based on a volatile tracer assisted twice headspace extraction gas chromatographic technique. The feasibility study showed that n-butanol was a suitable tracer to be used in this method. The results showed that the present method had a good precision (with the relative standard deviation < 0.86%) and good accuracy (in which the relative differences were within 7.94% when compared with the reference method). The present method is simple and practical. It can conduct an automated measurement when a batch sample testing is required.

Novel method for the determination of average molecular weight of natural polymers based on 2D DOSY NMR and chemometrics: Example of heparin

Apart from the characterization of impurities, the full characterization of heparin and low molecular weight heparin (LMWH) also requires the determination of average molecular weight, which is closely related to the pharmaceutical properties of anticoagulant drugs.To determine average molecular weight of these animal-derived polymer products, partial least squares regression (PLS) was utilized for modelling of diffused-ordered spectroscopy NMR data (DOSY) of a representative set of heparin (n=32) and LMWH (n=30) samples. The same sets of samples were measured by gel permeation chromatography (GPC) to obtain reference data. The application of PLS to the data led to calibration models with root mean square error of prediction of 498Da and 179Da for heparin and LMWH, respectively. The average coefficients of variation (CVs) did not exceed 2.1% excluding sample preparation (by successive measuring one solution, n=5) and 2.5% including sample preparation (by preparing and analyzing separate samples, n=5). An advantage of the method is that the sample after standard 1D NMR characterization can be used for the molecular weight determination without further manipulation. The accuracy of multivariate models is better than the previous results for other matrices employing internal standards. Therefore, DOSY experiment is recommended to be employed for the calculation of molecular weight of heparin products as a complementary measurement to standard 1D NMR quality control. The method can be easily transferred to other matrices as well.

Synthesis and characterization of polymethylmethacrylate grafted barley for treatment of industrial and municipal wastewater

In the present investigation, we have synthesized polymethylmethacrylate grafted barley (BAR-g-PMMA) using ceric ammonium nitrate as an initiator and methyl methacrylate as monomer in the presence of nitrogen atmosphere. The different grades of polymethylmethacrylate grafted barley were prepared by varying the concentration of initiator and monomer till the best grade was optimized. The synthesized grades have been confirmed by different analytical techniques like FTIR spectra, elemental analysis, TGA analysis, XRD analysis, intrinsic viscosity measurement, SEM morphology and number average molecular weight determination. The flocculation efficiency of the developed materials has been tested in coal fine, iron ore and kaolin suspensions. The best grade showed 86, 75 and 82% flocculation efficiency in coal fine, iron ore and kaolin suspension respectively and this was found to be 1.21, 1.25 and 1.24 times better than commercial flocculant Polyacrylamide. The settling rate was also determined during flocculation study. This material was further applied for treatment of municipal waste water. The acute oral toxicity of this material has been studied following Organization of Economic Co-operation and Development (OECD) guidelines showing its non toxic nature. Overall, on the basis of the above results, the developed non toxic graft copolymers can be safely used for treatment of the municipal as well as industrial waste water.

Enhanced polymer flooding using a novel nano‐scale smart polymer: Experimental investigation

AbstractPolymer flooding is a well‐known commercial method among enhanced oil recovery (EOR) methods. Despite its successful development, this method could still be improved considerably by utilizing new polymeric materials and systems. The main objective of this study is the implementation of smart‐covered polymer particles (SCPP) prepared by multistep inverse emulsion polymerization, to improve polymer flooding efficiency. Successive to the average molecular weight determination of the core polymer using the dilute solution method, the dissolution behaviour of SCPPs is examined at reservoir temperature in a specific setup. In addition to investigating the efficiency of SCPP flooding, polymer flooding experiments in a micromodel setup are examined. The flooding efficiency of conventional polyacrylamide and the newly developed SCPP solutions are compared with the water flooding process. Our results provide new insight into the ability of coated polymers to enhance the recovery efficiency of polymer flooding processes.

Characterization of ZnO Nanoparticles using Superconducting Tunnel Junction Cryodetection Mass Spectrometry.

Zinc oxide (ZnO) nanoparticles coated with either n-octylamine (OA) or α-amino poly(styrene-co-acrylonitrile) (PSAN) ligands (L) have been analyzed using laser desorption/ionization and matrix assisted laser desorption/ionization (MALDI) time-of-flight (TOF) superconducting tunnel junction (STJ) cryodetection mass spectrometry. STJ cryodetection has the advantage of high m/z detection and allows for the determination of average molecular weights and dispersities for 500-600 kDa ZnO-L nanoparticles. The ability to detect the relative energies deposited into the STJs has allowed for investigation of ZnO-L metastable fragmentation. ZnO-L precursor ions gain enough internal energy during the MALDI process to undergo metastable fragmentation in the flight tube. These fragments produced a lower energy peak, which was assigned as ligand-stripped ZnO cores whereas the individual ligands were at too low of an energy to be observed. From these STJ energy resolved peaks, the average weight percentage of inorganic material making up the nanoparticle was determined, where ZnO-OA and ZnO-PSAN nanoparticles are comprised of ~62% and ~68% wt ZnO, respectively. In one example, grafting densities were calculated based on the metastable fragmentation of ligands from the core to be 16 and 1.1 nm-2 for ZnO-OA and ZnO-PSAN, respectively, and compared with values determined by thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Graphical Abstract ᅟ.

Extensively deacetylated high molecular weight chitosan from the multistep ultrasound-assisted deacetylation of beta-chitin

High intensity ultrasound irradiation was used to convert beta-chitin (BCHt) into chitosan (CHs). Typically, beta-chitin was suspended in 40% (w/w) aqueous sodium hydroxide at a ratio 1/10 (gmL−1) and then submitted to ultrasound-assisted deacetylation (USAD) during 50min at 60°C and a fixed irradiation surface intensity (52.6Wcm−2). Hydrogen nuclear magnetic resonance spectroscopy and capillary viscometry were used to determine the average degree of acetylation (DA‾) and viscosity average degree of polymerization (DPv‾), respectively, of the parent beta-chitin (DA‾=80.7%; DPv‾=6865) and USAD chitosans. A first USAD reaction resulted in chitosan CHs1 (DA‾=36.7%; DPv‾=5838). Chitosans CHs2 (DA‾=15.0%; DPv‾=5128) and CHs3 (DA‾=4.3%; DPv‾=4889) resulted after repeating the USAD procedure to CHs1 consecutively once and twice, respectively. Size-exclusion chromatography analyzes allowed the determination of the weight average molecular weight (Mw‾) and dispersity (Ð) of CHs1 (Mw‾=1,260,000gmol−1; Ð=1.4), CHs2 (Mw‾=1,137,000gmol−1; Ð=1.4) and CHs3 (Mw‾=912,000gmol−1; Ð=1.3). Such results revealed that, thanks to the action of high intensity ultrasound irradiation, the USAD process allowed the preparation of unusually high molecular weight, randomly deacetylated chitosan, an important breakthrough to the development of new high grade chitosan-based materials displaying superior mechanical properties.

Formulation and development of plasma volume expander using natural and modified starch from Solanum tuberosum.

Background:To formulation and development of plasma volume expander (PVE) by using natural and modified starch from Solanum tuberosum. The function of blood circulation is to provide the needs of the body tissues and to maintain an appropriate environment in all tissue fluids of the body for the optimal survival and functions of the cells. Rapid restoration of the blood volume is necessary to decrease reduction in the amount of the blood. The PVEs are isotonic colloidal solutions, act by increasing the osmotic pressure of the intravascular compartment, which leads to the influx of the interstitial fluids through the capillary pore which, in turn, leads to the increase in the volume of the blood. Therefore, there is a need to discover the PVE with less side effects. The main aim of the present study is to use amylopectin as PVEs, fractionated from natural and modified starch obtained from S. tuberosum.Methods:The starch extracted from the normal grains and the tubers of potatoes was selected for the production of starch. Statistical analysis includes in vitro characterization that involves viscosity studies, plasma–product interaction, osmotic pressure detection, molecular weight–viscosity relationship, determination of weight average molecular weight, enzymatic interaction, and in vivo characterization such as toxicity studies and the effect of the products on the blood coagulation. The isolated starch and fractionated amylopectin were analyzed for the physicochemical characteristics.Result and Conclusion:The amylopectin fractionated from isolated starch from grains and tubers of potatoes can be used as PVE, as per the outcome of the study.

Jojoba modified polymers as performance modifiers additives for engine oil

Purpose – The purpose of this paper is to prepare novel types of copolymers and terpolymers depending on jojoba, and using them as additives for lubricating oil. Design/methodology/approach – Copolymerization of 1 mole of jojoba with 2 moles of vinyl acetate and copolymerization of 1 mole of jojoba with 2 moles of vinyl pyrrolidone were carried out. Then, two series of terpolymers were prepared by reacting (jojoba: vinyl acetate: alkylacrylate) and (jojoba: vinyl pyrrolidone: alkylacrylate), using free radical chain addition polymerization. Elucidation of the prepared polymers was carried out by using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The thermal stability of the prepared polymers was determined. The prepared polymers were evaluated as viscosity index improvers and pour point depressants for lubricating oil. Findings – It was found that the viscosity index increases with increasing the alkyl chain length of alkylacrylate. The effect of the monomer type was studied, and it was found that the polymers depending on vinyl acetate have great effect as viscosity index improvers and pour point depressants for lubricating oil. Originality/value – The polymerization of jojoba as different copolymers and terpolymers was carried out. The great influence of the prepared additives on modification of the viscosity properties and pour point of the oil was observed.

Terpolymers for modifying the performance properties of engine oil

Nine terpolymers consisting of (jojoba: alkylacrylate: α-olefins) backbone were synthesized via free radical chain addition polymerization and determined using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The alkylacrylates used were (dodecylacrylate, tetradecylacrylate and hexadecylacrylate), while α-olefins used were (dodecene, tetradecene and hexadecane). The monomers’ ratio used for polymerization was (1:1:1). It was found that the molecular weight increases with increasing the alkyl chain length of both alkylacrylate and α-olefins used. The thermal stability of the synthesized terpolymers was determined using thermal gravimetric analysis and differential scanning calorimetry. The prepared polymers were evaluated as performance modifiers (viscosity index improvers and pour point depressants) for free additives lube oil (SAE-30). It was found that the viscosity index increases with increasing the alkyl chain length, molecular weight and concentration of used terpolymer. The effect of the prepared terpolymers on the pour point of lube oil was studied and it was found that the pour point of lube decreases (more negative) with decreasing the alkyl chain length of both alkylacrylate and α-olefin used.

Preparation and molecular characterization of chitosans obtained from shrimp (Litopenaeus vannamei) shells.

Four chitosan samples were prepared from shrimp shells without deproteination and decoloration steps, by a deacetylation process at 2 reaction times (2 and 4 h) and with/without using a reducing agent (R.A.). Variations in the physicochemical properties of the final products were analyzed. Viscosity average molecular weight (Mw) determinations demonstrated the protective action of the R.A. on the molecular oxidative degradation. Oppositely, an increase on the reaction time produced samples with low Mw. Deacetylation degrees (DDs) were chemically evaluated by the nitrogen content and by spectroscopic techniques as infrared and nuclear magnetic resonance. The existing differences in crystallinity were studied by X-ray diffraction. Differential scanning calorimetry and thermogravimetry were used to demonstrate the dehydration and thermal degradation processes of the different chitosans. A novel method from calorimetric profiles is presenting for DD determinations of chitosan, which achieved highly satisfactory results (linear fit and Pearson's correlation coefficient) and is proposed to be generally extended to complex curves application.

SEDFIT-MSTAR: molecular weight and molecular weight distribution analysis of polymers by sedimentation equilibrium in the ultracentrifuge.

Sedimentation equilibrium (analytical ultracentrifugation) is one of the most inherently suitable methods for the determination of average molecular weights and molecular weight distributions of polymers, because of its absolute basis (no conformation assumptions) and inherent fractionation ability (without the need for columns or membranes and associated assumptions over inertness). With modern instrumentation it is also possible to run up to 21 samples simultaneously in a single run. Its application has been severely hampered because of difficulties in terms of baseline determination (incorporating estimation of the concentration at the air/solution meniscus) and complexity of the analysis procedures. We describe a new method for baseline determination based on a smart-smoothing principle and built into the highly popular platform SEDFIT for the analysis of the sedimentation behavior of natural and synthetic polymer materials. The SEDFIT-MSTAR procedure - which takes only a few minutes to perform - is tested with four synthetic data sets (including a significantly non-ideal system), a naturally occurring protein (human IgG1) and two naturally occurring carbohydrate polymers (pullulan and λ-carrageenan) in terms of (i) weight average molecular weight for the whole distribution of species in the sample (ii) the variation in "point" average molecular weight with local concentration in the ultracentrifuge cell and (iii) molecular weight distribution.

Emulsification Properties and Molecular Weight Distribution of Combretum Glutinosum Gum

The determination of weight average molecular weight (Mw) and radius of gyration (Rg) of Habeil gum was performed on a gel permeation chromatography-multi angle laser light scattering (GPC-MALLS) system. The results showed three main components of Combretum glutinosum gum designated arabinogalactan protein (AGP), arabinogalactan (AG) and glycoprotein (GP). The Mw of the freeze dried soluble part, freeze dried deacetylated gum, and freeze dried calcium-free gum were 2.06×106, 8.03×105, and 1.40×106 g /mol, respectively. The Mw of hydrophilic and hydrophobic components collected from soluble part gum are 3.16×106 and 6.08×105 g /mol, respectively, while the Mw of hydrophilic and hydrophobic components collected from deacetylated gum are 1.39×106 and 8.36×105 g /mol, respectively. Emulsification studies of the gum fractions showed lowest degree of span value than the starting material indicating good uniformity and increasing in adsorption of protein on oil droplet surface. The results of emulsion studies indicated that a blend of 50% w/w deacetylated Combretum glutinosum gum and 50% w/w Acacia Senegal produced better emulsification properties than the pure mother gum.

Microwave initiated synthesis of polyacrylamide grafted Casein (CAS-g-PAM)–Its application as a flocculant

Modification of the milk protein ‘casein’ has been carried out through microwave initiated graft copolymerization of acrylamide. The synthesis was optimized in terms of microwave irradiation time and monomer (acrylamide) concentration. The synthesized graft copolymers have been characterized by intrinsic viscosity measurement, elemental analysis, FTIR spectroscopy, scanning electron microscopy (SEM) and number average molecular weight determination through osmometry; taking the starting material (casein) as reference. Further, flocculation efficacy of various grades of the grafted product were studied and compared to that of the starting material ‘casein’ by Jar test and settling test procedure, in 1% coal-fine suspension.

Quality Control Aspects: A Simple Method for Estimation of Ethyl Alcohol in Oxy Diesel by NMR Spectroscopy

A direct and rapid method for the estimation of ethyl alcohol in oxy diesel based on NMR (1H, 13C) spectroscopic techniques has been developed. The estimation has been carried out by the methods (a) based on the determination of average group molecular weight (GMW) of the diesel and alcohol and (b) with precalibration of quantitative alcohol-diesel blends. Both the methods are independent of source, type, and nature of diesel (conventional, hydrocracked, hydrodesulfurization) produced by any of refinery processes. The precalibration method requires the use of standards for calibration, where as the GMW method does not require any. The methods have been tried on alcohol-diesel blends in the range of 1.0–10.0% w/w and will be applicable for quality control purposes in blending plant. The statistical treatment of theoretical and estimated values have shown excellent correlation (R 2 = .99). The effects of the spectral interference of emulsifier and coupler, which are added to emulsify the blends, on the chemical shift of alcohol signals in the 1H/13C-NMR spectra have also been studied.

Aqueous size exclusion chromatography in semimicro and micro-columns by newly synthesized monodisperse macroporous hydrophilic beads as a stationary phase

A new class of monodisperse macroporous beads in the hydrophilic form were synthesized by seeded microsuspension copolymerization of two acrylic crosslinking agents, glycerol dimethacrylate (GDMA) and glycerol-1,3-diglycerolate diacrylate (GDGDA). The monodisperse porous poly(glycerol dimethacrylate- co-glycerol-1,3-diglycerolate diacrylate), poly(GDMA- co-GDGDA) beads were highly hydrophilic in nature due to hydroxyl functionality resulting from both crosslinking agents. The beads with different particle sizes between 4.5 and 6.7 μm and with different porous properties were obtained by changing the seed latex to monomer ratio. The bead size decreased, the average pore size increased and the specific surface area decreased with increasing seed latex to monomer ratio. Poly(GDMA- co-GDGDA) beads were slurry packed in microbore and semimicro-HPLC columns and successfully used as a stationary phase in aqueous size exclusion chromatography (SEC) mode in a micro-liquid chromatography system. The aqueous SEC runs were performed by using dextran standards in the molecular weight range of 1000–670,000 Da. SEC calibration curves exhibiting linearity in a wider range of molecular weight were obtained with the semi-micro and micro-HPLC columns packed with the poly(GDMA- co-GDGDA) beads synthesized with the seed latex to monomer ratios of 0.038 and 0.058 g/mL. The dextran standards could be eluted in an analysis time shorter than 2 min using micro or semi-micro columns packed with poly(GDMA- co-GDGDA) beads as stationary medium. These packings are suitable for molecular weight determination between 5 × 10 3 and 5 × 10 5 Da in the aqueous medium by using mobile phase flow rates in the range of 25–250 μL/min. The average molecular weight determinations of different water soluble polymers, an ionic polymer, poly(2-dimethylaminoethyl methacrylate), a zwitterionic polymer, poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide), and a non-ionic polymer, poly(vinyl alcohol) were performed on a semimicro-column packed with the poly(GDMA- co-GDGDA) beads. Satisfactory results were obtained in the molecular weight determination of hydrophilic polymers by aqueous SEC.