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Bernd Trathnigg - One of the best experts on this subject based on the ideXlab platform.
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liquid exclusion adsorption chromatography a new technique for isocratic separation of nonionic surfactants iv two dimensional separation of Fatty Alcohol ethoxylates with focusing of fractions
Journal of Chromatography A, 2002Co-Authors: Bernd Trathnigg, Christina RappelAbstract:Abstract Fatty Alcohol ethoxylates can be analyzed using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. Transfer of fractions from the first to the second dimension is achieved using the full adsorption–desorption (FAD) technique. The peaks of interest in the first dimension are trapped on a short precolumn before injecting them into the second dimension. Full adsorption is achieved by increasing the water content in the mobile phase before the FAD column. When the fractions are desorbed by switching to the mobile phase of the second dimension, they are focused and reconcentrated. In this way, a full resolution of oligomers is achieved. As both dimensions are run in isocratic mode, density and refractive index detection can be applied, which allows an accurate quantitation.
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liquid exclusion adsorption chromatography a new technique for isocratic separation of nonionic surfactants iii two dimensional separation of Fatty Alcohol ethoxylates
Journal of Chromatography A, 2001Co-Authors: Bernd Trathnigg, Manfred Kollroser, Christina RappelAbstract:Abstract A quantitatively accurate mapping of lower Fatty Alcohol ethoxylates can be achieved using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. With coupled density and refractive index detection in both dimensions, the contribution of preferential solvation can also be estimated. In most cases, however, the use of refractive index detection alone also yields satisfactory results.
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liquid exclusion adsorption chromatography a new technique for isocratic separation of nonionic surfactants ii quantitation in the analysis of Fatty Alcohol ethoxylates
Journal of Chromatography A, 2001Co-Authors: Bernd TrathniggAbstract:Abstract A new technique of liquid chromatography, which allows baseline separation of Fatty Alcohol ethoxylates with up to 15–20 ethylene oxide units under isocratic conditions allows an accurate quantitative analysis of single hydrophobic chain surfactants. Using density and refractive index detection, the accurate weight fractions of the individual oligomers are obtained. Moreover, the contribution of preferential solvation can be determined. With refractive index detection alone, good accuracy can also be achieved.
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liquid exclusion adsorption chromatography new technique for isocratic separation of nonionic surfactants i retention behaviour of Fatty Alcohol ethoxylates
Journal of Chromatography A, 2001Co-Authors: Bernd Trathnigg, Alexei GorbunovAbstract:A new technique of liquid chromatography is described, which allows a baseline separation of Fatty Alcohol ethoxylates with 15-20 ethylene oxide units under isocratic conditions. The new method is based on a combination of two different chromatographic modes for the individual structural units: size exclusion for the poly(oxyethylene) chain and adsorption interaction for the hydrophobic end fragments. A theory is provided for this mixed exclusion-adsorption mode of liquid chromatography. Chromatographic data are found to be in a good agreement with this theory.
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theory of liquid adsorption chromatography of macromolecules applied to polyethylene glycol and Fatty Alcohol ethoxylates
Journal of Chromatography A, 1997Co-Authors: Bernd Trathnigg, B Maier, Alexei Gorbunov, Alexander SkvortsovAbstract:Liquid adsorption chromatography retention modes of poly(ethylene glycol) (PEG), its mono- and dimethyl ethers (MMEs and DMEs) and also of Fatty Alcohol ethoxylates (FAEs) are studied both experimentally and theoretically. The experimental system under investigation was a Spherisorb S5W 80 A column and isopropanol–water as the mobile phase. At various compositions of the mobile phase (in the range of 75 to 87% of isopropanol) chromatograms exhibiting good peak resolution were obtained and the dependencies of the elution volume on the number of repeating EO units for both PEG and FAE samples evaluated on the basis of a closer inspection of the chromatographic data. The experiments did not reveal any differences between the chromatographic behavior of PEGs, MMEs and DMEs, while the FAEs gave substantially smaller values of elution volume at all mobile phase compositions. These data were interpreted by using a molecular-statistic theory of homopolymers (to describe both PEG, MME and DME) and two-block copolymers (for FAEs) based on a continuum Gaussian chain model of macromolecules and a slit-like model of pores of stationary phase, wide pore approximation and the adsorption chromatography mode for PEG molecules were assumed in the development of this theory. This theory described very well the experimental data obtained, and two thermodynamic parameters characterizing interactions of EO units of PEG and both EO and (CH2)n chains of FAE molecules with the adsorbent pore walls have been determined from the comparison of the theory and the experiments. Although the mean thickness of adsorbed oxyethylene chain, H, was estimated as being equal to about 3.5–4.5 A, H proved to be slightly decreasing with increasing isopropanol content in mobile phase. Chromatograms visualizing the adsorption of PEG and FAE molecules are presented, and the correspondence between the theoretical approach and the experimental situation under investigation is discussed.
Harald Pasch - One of the best experts on this subject based on the ideXlab platform.
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analysis of Fatty Alcohol ethoxylates regarding chain length and endgroups by maldi tof ms using collision induced dissociation
Macromolecular Chemistry and Physics, 2012Co-Authors: Valentina Mass, Thomas Ostrowski, Karsten Rode, Frank Rittig, Harald PaschAbstract:MALDI-TOF MS is used to analyze the chain lengths and endgroups of Fatty Alcohol ethoxylates based on the fragmentation behavior in collision-induced dissociation. MALDI-CID-TOF2 of the ethoxylates results in complex fragmentation patterns that mirror the fragmentation of the ethylene oxide oligomer chain and the Fatty alocohol endgroups. Characteristic fragment patterns are obtained that facilitate the interpretation of the fragmentation behavior of the Fatty Alcohol ethoxylates. Linear and branched endgroups can be differentiated and specific fragments are identified that are characteristic for the cleavage between the polymer chain and the endgroup. These “marker” fragments are used to determine the oligomer chain length and the number of carbons per endgroup.
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two dimensional chromatography of complex polymers 8 separation of Fatty Alcohol ethoxylates simultaneously by end group and chain length
Journal of Separation Science, 2010Co-Authors: Jacquesantoine Raust, Adele Bruell, Pritish Sinha, Wolf Hiller, Harald PaschAbstract:A comprehensive two-dimensional liquid chromatography system was developed to precisely describe the molecular heterogeneity of Fatty Alcohol ethoxylates. The end-group functionality was analyzed by gradient HPLC while ethylene oxide oligomer distributions were characterized by liquid adsorption chromatography. A baseline separation of all functionality fractions irrespective of the ethylene oxide oligomer chain length was achieved on nonpolar X-Terra® C18 with a methanol–water gradient, whereas an isocratic flow of isopropanol–water on a polar Chromolith® Si column gave a separation according to the oligomer chain length without interference of the end-group distribution. The combination of these two methods to conduct online two-dimensional liquid chromatography experiments resulted in a comprehensive two-dimensional picture on the molecular heterogeneity of the sample.
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hplc nmr of Fatty Alcohol ethoxylates
Magnetic Resonance in Chemistry, 2005Co-Authors: Wolf Hiller, Eberhard Hoffmann, Adele Brull, Dimitris S. Argyropoulos, Harald PaschAbstract:The application of HPLC–NMR for the analysis of a mixture of Fatty Alcohol ethoxylates (FAEs) is described. The use of the new generation, cryogenically cooled probes is investigated in respect of the sensitivity advantage that they provide. The FAE mixture is separated using liquid chromatography at the critical point of adsorption. The ability of the method to differentiate between the different end groups and the degree of polymerization of the mixture constituents is investigated. Both on-flow and stop-flow HPLC–NMR techniques were used together with two-dimensional NMR spectroscopy. The results are compared with those obtained by using an evaporative light scattering detector for the HPLC. Copyright © 2005 John Wiley & Sons, Ltd.
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matrix assisted laser desorption ionization mass spectrometry of synthetic polymers 7 analysis of Fatty Alcohol ethoxylates by coupled liquid chromatography at the critical point of adsorption and maldi tof mass spectrometry
Macromolecular Symposia, 2003Co-Authors: Karlheinz Spriestersbach, Karsten Rode, Harald PaschAbstract:Fatty Alcohol ethoxylates can be analyzed efficiently with respect to functionality and molar mass by coupled liquid chromatography and MALDI-TOF mass spectrometry. Both techniques are coupled via a robotic interface, where the matrix is coaxially added to the eluate and spotted dropwise onto the MALDI target. It is shown that liquid chromatography at critical conditions of adsorption coupled to MALDI-TOF yield useful structural information on oligomer masses and chemical composition. In particular, the analysis of technical Fatty Alcohol ethoxylates by LC-CC/MALDI-TOF reveals the presence of different functionality fractions in one sample. The oligomer distributions of all functionality fractions are determined.
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on line hplc 1h nmr coupling for the analysis of Fatty Alcohol ethoxylates
Polymer Bulletin, 1997Co-Authors: Gotz Schlotterbeck, Harald Pasch, Klaus AlbertAbstract:The characterisation of Fatty Alcohol ethoxylate based surfactants by on-line LC-NMR coupling is described. Different surfactant mixtures were separated by a mixed exclusion-adsorption method of liquid chromatography and simultaneously characterised by 1H-NMR spectroscopy. Information about the degree of oligomerisation of the ethylene oxide chain and the chemical structure of the endgroups can be obtained in a one-step experiment.
Christina Rappel - One of the best experts on this subject based on the ideXlab platform.
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liquid exclusion adsorption chromatography a new technique for isocratic separation of nonionic surfactants iv two dimensional separation of Fatty Alcohol ethoxylates with focusing of fractions
Journal of Chromatography A, 2002Co-Authors: Bernd Trathnigg, Christina RappelAbstract:Abstract Fatty Alcohol ethoxylates can be analyzed using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. Transfer of fractions from the first to the second dimension is achieved using the full adsorption–desorption (FAD) technique. The peaks of interest in the first dimension are trapped on a short precolumn before injecting them into the second dimension. Full adsorption is achieved by increasing the water content in the mobile phase before the FAD column. When the fractions are desorbed by switching to the mobile phase of the second dimension, they are focused and reconcentrated. In this way, a full resolution of oligomers is achieved. As both dimensions are run in isocratic mode, density and refractive index detection can be applied, which allows an accurate quantitation.
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liquid exclusion adsorption chromatography a new technique for isocratic separation of nonionic surfactants iii two dimensional separation of Fatty Alcohol ethoxylates
Journal of Chromatography A, 2001Co-Authors: Bernd Trathnigg, Manfred Kollroser, Christina RappelAbstract:Abstract A quantitatively accurate mapping of lower Fatty Alcohol ethoxylates can be achieved using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. With coupled density and refractive index detection in both dimensions, the contribution of preferential solvation can also be estimated. In most cases, however, the use of refractive index detection alone also yields satisfactory results.
Mariana C Costa - One of the best experts on this subject based on the ideXlab platform.
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solid liquid phase equilibrium diagrams of binary mixtures containing Fatty acids Fatty Alcohol compounds and tripalmitin using differential scanning calorimetry
Fluid Phase Equilibria, 2019Co-Authors: Fernanda Paludetto Pelaquim, L P Cardoso, Flavio Cardoso De Matos, Eduardo A C Batista, Antonio J A Meirelles, Mariana C CostaAbstract:Abstract Fatty acids, Fatty Alcohol compounds and triacylglycerols (TAGs) present a significant role in industrial applications, mainly in food, cosmetics and pharmaceutical industries. In this study, eight solid-liquid phase diagrams composed by tripalmitin plus Fatty acids (capric acid, lauric acid, myristic acid, palmitic acid and stearic acid) and tripalmitin plus Fatty Alcohol compounds (1-decanol, 1-dodecanol and 1-tetradecanol) were studied using Differential Scanning Calorimetry (DSC) technique, optical microscopy and X-ray analysis. The phase diagrams formed by tripalmitin + Fatty acids (myristic acid, palmitic acid and stearic acid), present a eutectic behavior with a solid solution for tripalmitin (1) + myristic acid (4) system, and a monotectic behavior for tripalmitin + (capric acid and lauric acid) whereas the phase diagrams formed by tripalmitin + Fatty Alcohol compounds present a monotectic behavior and just one of them present a monotectic behavior with a solid solution (1-tetradecanol). The liquid phase was modelled using ideal assumption, 3-suffix Margules and NRTL models, adjusting its parameters. These models described properly the liquidus line of the systems studied.
Guillermo Ramisramos - One of the best experts on this subject based on the ideXlab platform.
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determination of Fatty Alcohol ethoxylates and alkylether sulfates by anionic exchange separation derivatization with a cyclic anhydride and liquid chromatography
Journal of Chromatography A, 2011Co-Authors: Miriam Beneitocambra, Ernesto F Simoalfonso, L Ripollseguer, Jose Manuel Herreromartinez, Guillermo RamisramosAbstract:A method for the separation, characterization and determination of Fatty Alcohol ethoxylates (FAE) and alkylether sulfates (AES) in industrial and environmental samples is described. Separation of the two surfactant classes was achieved in a 50:50 methanol–water medium by retaining AES on a strong anionic exchanger (SAX) whereas most FAE were eluted. After washing the SAX cartridges to remove cations, the residual hydrophobic FAE were eluted by increasing methanol to 80%. Finally, AES were eluted using 80:20 and 95:5 methanol–concentrated aqueous HCl mixtures. Methanol and water were removed from the FAE and AES fractions, and the residues were dissolved in 1,4-dioxane. In this medium, esterification of FAE and transesterification of AES with a cyclic anhydride was performed. Phthalic and diphenic anhydrides were used to derivatizate the surfactants in industrial samples and seawater extracts, respectively. Separation of the derivatized oligomers was achieved by gradient elution on a C8 column with acetonitrile/water in the presence of 0.1% acetic acid. Good resolution between both the hydrocarbon series and the successive oligomers within the series was achieved. Cross-contamination of FAE with AES and vice versa was not observed. Using dodecyl Alcohol as calibration standard, and correction of the peak areas of the derivatized oligomers by their respective UV–vis response factors, both FAE and AES were evaluated. After solid-phase extraction on C18, the proposed method was successfully applied to the characterization and determination of the two surfactant classes in industrial samples and in seawater.
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determination of Fatty Alcohol ethoxylates with diphenic anhydride derivatization and liquid chromatography with spectrophotometric detection a comparative study with other anhydrides
Journal of Chromatography A, 2009Co-Authors: Anna Micotormos, Ernesto F Simoalfonso, Federico Bianchi, Guillermo RamisramosAbstract:Abstract A method for the determination of Fatty Alcohol ethoxylates (FAEs) using diphenic anhydride as derivatization reagent and RP-HPLC separation with UV–vis detection is presented and compared to derivatization with maleic, phthalic, and other cyclic anhydrides. With these anhydrides, the reaction rates increased when urea was added to the reaction medium, and the yields did not decrease when the samples contained moderate amounts of water. Gradient elution on a C8 column was performed with water/acetonitrile in the presence of 0.1% acetic acid. The use of diphenic anhydride was advantageous for both the chromatographic separation and the detection. Specifically, sensitivity at 200 and 220 nm was significantly better for the FAE diphenates, resulting in lower limits of detection at both wavelengths for the diphenates than for the maleates and phthalates (up to 30 and 4.3 times lower at 220 nm, respectively). Response factors for the diphenates decreased less than those of the phthalates when the number of ethylene oxide units, m , increased, reaching a constant value of ca. 0.62 when m > 3. Peak symmetries and efficiencies were also better than those found for the other anhydrides. The optimized procedure was applied to the characterization and determination of FAEs in the effluent of a wastewater treatment plant and in sea water.
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determination of Fatty Alcohol ethoxylates by derivatization with phthalic anhydride followed by liquid chromatography with uv vis detection
Journal of Chromatography A, 2008Co-Authors: Anna Micotormos, Ernesto F Simoalfonso, Guillermo RamisramosAbstract:Abstract The esterification of Fatty Alcohol ethoxylates (FAEs) with phthalic anhydride in 1,4-dioxane was studied. At 110 °C and in the presence of urea, which increased the reaction rate, esterification was completed in 60 min. The reaction yield did not decrease when the sample contained up to 50% water. For the non-ethoxylated Alcohols, the UV–vis response factors of the derivatives were not significantly different from each other ( f = 1 for C12E0 as reference). The response factors decreased when the number of ethylene oxide units, m , increased, reaching constant values of ca. 0.40 and 0.65 for the n = 8 and 18 series, respectively, when m ≥ 3. Using a C8 column and gradient elution with acetonitrile/water plus 0.1% acetic acid, FAEs in industrial mixtures and cleaning products were characterized. At column temperatures of 25 and 35 °C, homologous series with even values of n from 8 up to 20, were resolved up to m = 14 and 18, respectively, and at 25 °C, series with consecutive even and odd values of n were resolved up to m = 7. Within the series, superior resolution of the ethoxymers with large values of m was achieved; however, the elution order was reversed for the m = 1 and 0 ethoxymers, which produced overlapping of a few peaks within the series. A simple procedure for the accurate prediction of the concentrations of all the ethoxymers in industrial samples was described. After preconcentration with C18 solid-phase extraction cartridges, FAEs were also characterized and quantified in environmental samples (river and sea water). The LODs were ca. 2 μM ( S / N = 3) in the injected solutions.
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on the determination of underivatised Fatty Alcohol ethoxylates by electrospray ionisation mass spectrometry
Journal of Chromatography A, 2006Co-Authors: Virginia Bernabezafon, Ernesto F Simoalfonso, Guillermo RamisramosAbstract:Abstract The oligomers of Fatty Alcohol ethoxylates (FAEs) exhibit large sensitivity differences in mass spectrometry with electrospray ionisation (ESI–MS) and atmospheric pressure chemical ionization (APCI). Standards of the oligomers from m = 1 to 7 ethylene oxide units (EOs) and linear alkyl chains from n = 10 to 18 carbon atoms were infused to examine the relative sensitivities or response factors in several media. The response factors of the [M + H]+ and [M + Na]+ peaks in 9:1 acetonitrile/water and methanol/water media containing acid buffers increased following irregular patterns when n and m increased. In methanol/water the response factors depended on the parity of m, being larger than the average trend for the oligomers with an even value of m with respect to those having an odd value. This was attributed to the presence of an uncompensated C–O–C or C–O–H dipole in the former oligomers. The advantages of using ESI over APCI and of measuring the [M + H]+ peaks in an acid methanol/water medium containing 0.1 M HCl are discussed. The advantages and limitations of using models of the response factors to evaluate oligomer concentrations with a reduced set of selected standards are examined. The determination of underivatised FAEs using acid media was made compatible with previous HPLC separation by implementing either a triconcentric nebulizer fed with an acid liquid sheath, or a capillary T-union inserted between the column outlet and the biconcentric nebulizer, and fed with an acid stream provided by a syringe pump.
