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Rosario Rodil - One of the best experts on this subject based on the ideXlab platform.
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in sample acetylation non porous Membrane assisted liquid liquid extraction for the determination of parabens and triclosan in water samples
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Eugenia Villaverdedesaa, Rosario Rodil, Iria Gonzalezmarino, Jose Benito Quintana, I Rodriguez, R CelaAbstract:A procedure for the determination of seven parabens (esters of 4-hydroxybenzoic acid), including the distinction between branched and linear isomers of propyl- and butyl-parabens and triclosan in water samples, was developed and evaluated. The procedure includes in-sample acetylation-Non-Porous Membrane-assisted liquid-liquid extraction and large volume injection-gas chromatography-ion trap-tandem mass spectrometry. Different derivatisation strategies were considered, i.e. post-extraction silylation with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide and in situ acylation with acetic anhydride (Ac(2)O) and isobutylchloroformate. Moreover, acceptor solvent and the basic catalyser of the acylation reaction were investigated. Thus, in situ derivatisation with Ac(2)O and potassium hydrogenphosphate (as basic catalyser) was selected. Potassium hydrogenphosphate overcomes some drawbacks of other basic catalysers, e.g. toxicity and bubble formation, while leads to higher responses. Subsequently, other experimental variables affecting derivatisation-extraction yield such as pre-stirring time, salt addition and volume of Ac(2)O were optimised by an experimental design approach. Under optimised conditions, the proposed method achieved detection limits from 0.1 to 1.4 ng L(-1) for a sample volume of 18 mL and extraction efficiencies, estimated by comparison with liquid-liquid extraction, between 46% (for methyl- and ethyl-parabens) and 110% (for benzylparaben). The reported sample preparation approach is free of matrix effects for parabens but affected for triclosan with a reduction of approximately 40% when wastewater samples are analysed; therefore, both internal and external calibration can be used as quantification techniques for parabens, but internal standard calibration is mandatory for triclosan. The application of the method to real samples revealed the presence of these compounds in raw wastewater at concentrations up to 26 ng mL(-1), the prevalence of the linear isomer of propylparaben (n-PrP), and the coexistence of the two isomers of butylparaben (i-BuP and n-BuP) at similar levels.
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non porous Membrane assisted liquid liquid extraction of uv filter compounds from water samples
Journal of Chromatography A, 2009Co-Authors: Rosario Rodil, Steffi Schrader, Monika MoederAbstract:Abstract A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes Non-Porous Membrane-assisted liquid–liquid extraction (MALLE) and LC–atmospheric pressure photoionisation (APPI)–MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene Membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made Membrane bags were prepared from low-density polyethylene in order to accommodate 100 μL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L−1 (OD-PABA) and 16 ng L−1 (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L−1 (BP-3) and 4381 ng L−1 (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L−1 (OC).
R Cela - One of the best experts on this subject based on the ideXlab platform.
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in sample acetylation non porous Membrane assisted liquid liquid extraction for the determination of parabens and triclosan in water samples
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Eugenia Villaverdedesaa, Rosario Rodil, Iria Gonzalezmarino, Jose Benito Quintana, I Rodriguez, R CelaAbstract:A procedure for the determination of seven parabens (esters of 4-hydroxybenzoic acid), including the distinction between branched and linear isomers of propyl- and butyl-parabens and triclosan in water samples, was developed and evaluated. The procedure includes in-sample acetylation-Non-Porous Membrane-assisted liquid-liquid extraction and large volume injection-gas chromatography-ion trap-tandem mass spectrometry. Different derivatisation strategies were considered, i.e. post-extraction silylation with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide and in situ acylation with acetic anhydride (Ac(2)O) and isobutylchloroformate. Moreover, acceptor solvent and the basic catalyser of the acylation reaction were investigated. Thus, in situ derivatisation with Ac(2)O and potassium hydrogenphosphate (as basic catalyser) was selected. Potassium hydrogenphosphate overcomes some drawbacks of other basic catalysers, e.g. toxicity and bubble formation, while leads to higher responses. Subsequently, other experimental variables affecting derivatisation-extraction yield such as pre-stirring time, salt addition and volume of Ac(2)O were optimised by an experimental design approach. Under optimised conditions, the proposed method achieved detection limits from 0.1 to 1.4 ng L(-1) for a sample volume of 18 mL and extraction efficiencies, estimated by comparison with liquid-liquid extraction, between 46% (for methyl- and ethyl-parabens) and 110% (for benzylparaben). The reported sample preparation approach is free of matrix effects for parabens but affected for triclosan with a reduction of approximately 40% when wastewater samples are analysed; therefore, both internal and external calibration can be used as quantification techniques for parabens, but internal standard calibration is mandatory for triclosan. The application of the method to real samples revealed the presence of these compounds in raw wastewater at concentrations up to 26 ng mL(-1), the prevalence of the linear isomer of propylparaben (n-PrP), and the coexistence of the two isomers of butylparaben (i-BuP and n-BuP) at similar levels.
Monika Moeder - One of the best experts on this subject based on the ideXlab platform.
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non porous Membrane assisted liquid liquid extraction of uv filter compounds from water samples
Journal of Chromatography A, 2009Co-Authors: Rosario Rodil, Steffi Schrader, Monika MoederAbstract:Abstract A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes Non-Porous Membrane-assisted liquid–liquid extraction (MALLE) and LC–atmospheric pressure photoionisation (APPI)–MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene Membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made Membrane bags were prepared from low-density polyethylene in order to accommodate 100 μL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L−1 (OD-PABA) and 16 ng L−1 (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L−1 (BP-3) and 4381 ng L−1 (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L−1 (OC).
Eugenia Villaverdedesaa - One of the best experts on this subject based on the ideXlab platform.
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in sample acetylation non porous Membrane assisted liquid liquid extraction for the determination of parabens and triclosan in water samples
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Eugenia Villaverdedesaa, Rosario Rodil, Iria Gonzalezmarino, Jose Benito Quintana, I Rodriguez, R CelaAbstract:A procedure for the determination of seven parabens (esters of 4-hydroxybenzoic acid), including the distinction between branched and linear isomers of propyl- and butyl-parabens and triclosan in water samples, was developed and evaluated. The procedure includes in-sample acetylation-Non-Porous Membrane-assisted liquid-liquid extraction and large volume injection-gas chromatography-ion trap-tandem mass spectrometry. Different derivatisation strategies were considered, i.e. post-extraction silylation with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide and in situ acylation with acetic anhydride (Ac(2)O) and isobutylchloroformate. Moreover, acceptor solvent and the basic catalyser of the acylation reaction were investigated. Thus, in situ derivatisation with Ac(2)O and potassium hydrogenphosphate (as basic catalyser) was selected. Potassium hydrogenphosphate overcomes some drawbacks of other basic catalysers, e.g. toxicity and bubble formation, while leads to higher responses. Subsequently, other experimental variables affecting derivatisation-extraction yield such as pre-stirring time, salt addition and volume of Ac(2)O were optimised by an experimental design approach. Under optimised conditions, the proposed method achieved detection limits from 0.1 to 1.4 ng L(-1) for a sample volume of 18 mL and extraction efficiencies, estimated by comparison with liquid-liquid extraction, between 46% (for methyl- and ethyl-parabens) and 110% (for benzylparaben). The reported sample preparation approach is free of matrix effects for parabens but affected for triclosan with a reduction of approximately 40% when wastewater samples are analysed; therefore, both internal and external calibration can be used as quantification techniques for parabens, but internal standard calibration is mandatory for triclosan. The application of the method to real samples revealed the presence of these compounds in raw wastewater at concentrations up to 26 ng mL(-1), the prevalence of the linear isomer of propylparaben (n-PrP), and the coexistence of the two isomers of butylparaben (i-BuP and n-BuP) at similar levels.
Liyuan Deng - One of the best experts on this subject based on the ideXlab platform.
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subsea natural gas dehydration in a Membrane contactor with turbulence promoter an experimental and modeling study
Chemical Engineering Journal, 2021Co-Authors: Mahdi Ahmadi, Arne Lindbrathen, Magne Hillestad, Liyuan DengAbstract:Abstract Subsea natural gas reservoirs are usually saturated with water vapor that causes corrosion in pipelines and forms hydrates blocking pipes and installations. In this work, the viability of the subsea natural gas dehydration in a Non-Porous Membrane contactor was evaluated experimentally and by modeling. A flat sheet composite Membrane is employed as the Membrane interface and a structured packing turbulence promoter was installed at the gas side. The water flux and the outlet dew point were measured at different operating conditions (e.g., pressures, liquid and gas flow rates). To estimate simultaneously the permeability, overall mass transfer coefficient, and outlet water content, a systematic approach was applied and a 1D-2D model was developed bypassing the liquid phase mass transfer resistance and solved numerically coupled with a developed correlation for axial dispersion coefficient. The results show an increase in transMembrane water flux to the highest values of 72 g/m2h and 53 g/m2h with increasing gas flow rate and pressure to 500 ml/min and 11 bara, respectively. The effect of using a turbulence promoter was evaluated, and a good agreement between the simulated and experimental results was obtained. The mass transfer resistance of a dense layer was found to be dominating compared to that of gas and liquid phase and the high pressure and high gas flow rate are favored in this process. This study shows that Membrane contactor enables effective water separation under subsea conditions. Installation of a turbulence promoter in the gas phase significantly reduced the water content in the outlet gas stream.
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CO2 capture using highly viscous amine blends in Non-Porous Membrane contactors
Chemical Engineering Journal, 2019Co-Authors: Luca Ansaloni, Hanna K Knuutila, Ardi Hartono, Muhammad Awais, Liyuan DengAbstract:Abstract New amine blends have shown a promising potential to reduce the energy penalty for CO2 capture in post combustion, making the deployment of carbon capture technologies one-step closer. However, their application at the industrial scale is threaten by their high volatility. Non-Porous Membrane contactors offer a viable solution to properly control amine emissions from these absorbents. In the present work, the CO2 capture performance of Non-Porous Membrane contactors using new amine blends as liquid phase was investigated in a temperature range typical for the absorption step (25–60 °C). Different amine blends with promising features in terms of cycling capacity and regeneration energy requirement were selected as liquid absorbents. Thin composite Membranes fabricated by coating a perfluoropolymer on the top of a porous polypropylene layer were used as the interface between the gas and the liquid. At room temperature, Membrane contactors using new absorbents exhibit a lower CO2 mass transfer coefficient compared to the benchmark (30 wt% MEA), possibly due to the high viscosity of these liquids. The modelling analysis suggests that the liquid boundary layer dominates the mass transfer resistance in the temperature range up to 40 °C, but at higher temperatures, the decrease of the solvent viscosity makes the mass transfer dominated by the Membrane phase. Interestingly, the new amine blends show better performance compared to the benchmark at higher CO2 concentrations in feed gas, highlighting a good potential to capture CO2 from concentrated flue gas from steel/cement industry or to upgrade biogas.