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Johan A. Martens - One of the best experts on this subject based on the ideXlab platform.
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In situ FT-IR investigation of etravirine speciation in pores of SBA-15 Ordered Mesoporous Silica material upon contact with water.
Molecular Pharmaceutics, 2013Co-Authors: Randy Mellaerts, Patrick Augustijns, Guy Van Den Mooter, Elie J. Fayad, Mickaël Rivallan, Frédéric Thibault-starzyk, Johan A. MartensAbstract:Ordered Mesoporous Silica (OMS) has been recognized as promising adsorbent material for drug molecules with low aqueous solubility. The release of drug molecules from OMS upon contact with aqueous ...
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risk assessment of premature drug release during wet granulation of Ordered Mesoporous Silica loaded with poorly soluble compounds itraconazole fenofibrate naproxen and ibuprofen
European Journal of Pharmaceutics and Biopharmaceutics, 2012Co-Authors: Monica Vialpando, Johan A. Martens, Floris Ackhuijs, Guy Van Den MooteAbstract:In this study, the potential of wet granulation of Ordered Mesoporous Silica (OMS) material was evaluated to assess the risk of premature drug release during processing and to improve the bulk powder flow properties and compactibility for the development of an immediate release oral dosage form. The poorly water soluble model compounds, itraconazole, fenofibrate, naproxen, and ibuprofen were loaded into the model OMS, COK-12, and granulated using a polyvinylpyrrolidone (PVP) binder solution. Preliminary assessments were made with itraconazole loaded COK-12 to study the effects of the initial drug load, binder concentration, binder addition rate, and granulation temperature on premature drug release. Comparison to pure COK-12 revealed particle size enlargement and enhanced powder flow based on Carr Index and Hausner Ratio results. Following compression to 120 MPa, the compactibility of the granulated material also improved when compared to the untreated COK-12. In vitro release of itraconazole from the compressed granulated material was assessed with and without the disintegrant, croscarmellose sodium. Incorporation of 2.4 wt. croscarmellose sodium prior to compression successfully recovered the slight release loss following compression. To assess premature drug release, developments made with itraconazole loaded COK-12 were applied to loaded fenofibrate, naproxen, and ibuprofen. Results from modulated differential scanning calorimetry (MDSC) indicated that the risk of premature drug release during wet granulation was primarily compound dependent. These findings highlight challenges in preparation for a successful manufacturing process of OMS based formulations.
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preventing release in the acidic environment of the stomach via occlusion in Ordered Mesoporous Silica enhances the absorption of poorly soluble weakly acidic drugs
Journal of Pharmaceutical Sciences, 2011Co-Authors: Michiel Van Speybroeck, Jan Van Humbeeck, Pieter Annaert, Randy Mellaerts, Guy Van Den Mooter, Johan A. Martens, Patrick AugustijnsAbstract:ABSTRACT This study aimed to assess the pharmaceutical performance of formulations consisting of either indomethacin or glibenclamide and the Ordered Mesoporous Silica material SBA‐15. Both compounds were loaded on SBA‐15 via solvent impregnation. Adsorption in the SBA‐15 mesopores was confirmed using nitrogen physisorption. Differential scanning calorimetry results suggested that both compounds were dispersed monomolecularly onto the SBA‐15 surface. In in vitro experiments simulating the gastric‐to‐intestinal transition, the release of both compounds from SBA‐15 remained under 1% in simulated gastric fluid (SGF, pH 1.2), whereas both drugs were completely released within 10 min after transfer to fasted state simulated intestinal fluid (FaSSIF, pH 6.5). As both drugs exhibited very rapid precipitation from the supersaturated state in SGF, the preferential release in FaSSIF—where conditions are more favourable by virtue of either much higher solubility (indomethacin) or more stable supersaturation (glibenclamide)—was considered crucial towards achieving optimal absorption. This hypothesis was confirmed by an in vivo study, where the extent of absorption of a glibenclamide–SBA‐15 formulation was found to be more than fourfold higher than that of the commercial glibenclamide product Daonil®. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4864–4876, 2011
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Continuous Synthesis Process of Hexagonal Nanoplates of P6m Ordered Mesoporous Silica
Journal of the American Chemical Society, 2011Co-Authors: Jasper Jammaer, Titus S. Van Erp, Alexander Aerts, Christine E. A. Kirschhock, Johan A. MartensAbstract:Hexagonally Ordered Mesoporous Silica coined COK-12 was synthesized in a continuous process by combining streams of sodium Silicate and citric acid/sodium citrate buffered solution of (ethylene oxide)20–(propylene oxide)70–(ethylene oxide)20 triblock copolymer (Pluronic P123) from separate reservoirs. COK-12 precipitated spontaneously upon combining both streams at nearly neutral pH and ambient temperature. Stable intermediates of the COK-12 formation process could be prepared by limiting sodium Silicate addition. Investigation of these intermediates using small-angle X-ray scattering revealed COK-12 formed via an assembly process departing from spherical uncharged core–shell P123-Silica micelles. The sterical stabilization of these micelles decreased upon accumulation of Silicate oligomers in their shell. Aggregation of the spherical micelles led to cylindrical micelles, which aligned and adopted the final hexagonal organization. This unprecedentedly fast formation of P6m Ordered Mesoporous Silica was ca...
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evaluation of Ordered Mesoporous Silica as a carrier for poorly soluble drugs influence of pressure on the structure and drug release
Journal of Pharmaceutical Sciences, 2011Co-Authors: Monica Vialpando, Johan A. Martens, Alexander Aerts, Jeroen Persoons, Guy Van Den MooterAbstract:ABSTRACT Ordered Mesoporous Silica (OMS) materials are considered a promising drug delivery system for the dissolution enhancement of poorly soluble compounds. The purpose of the present work was to determine structural and behavioral changes of compressed OMS material necessary for the development of an immediate‐release oral‐dosage formulation. Two types of OMS materials (SBA‐15 and COK‐12) were subjected to pressures both in and beyond the tabletting region and characterized by nitrogen physisorption, scanning and transmission electron microscopy, small‐angle X‐ray scattering, and differential scanning calorimetry. Itraconazole was used as the poorly soluble model drug and the release process with respect to pressure was determined in vitro . The resulting decreased drug release due to increased pressure was recovered by incorporating a plastically deforming material such as microcrystalline cellulose in combination with croscarmellose sodium. These findings further elucidate the understanding of their structural behavior for the advancement as a drug delivery carrier. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:3411–3420, 2011
Randy Mellaerts - One of the best experts on this subject based on the ideXlab platform.
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In situ FT-IR investigation of etravirine speciation in pores of SBA-15 Ordered Mesoporous Silica material upon contact with water.
Molecular Pharmaceutics, 2013Co-Authors: Randy Mellaerts, Patrick Augustijns, Guy Van Den Mooter, Elie J. Fayad, Mickaël Rivallan, Frédéric Thibault-starzyk, Johan A. MartensAbstract:Ordered Mesoporous Silica (OMS) has been recognized as promising adsorbent material for drug molecules with low aqueous solubility. The release of drug molecules from OMS upon contact with aqueous ...
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preventing release in the acidic environment of the stomach via occlusion in Ordered Mesoporous Silica enhances the absorption of poorly soluble weakly acidic drugs
Journal of Pharmaceutical Sciences, 2011Co-Authors: Michiel Van Speybroeck, Jan Van Humbeeck, Pieter Annaert, Randy Mellaerts, Guy Van Den Mooter, Johan A. Martens, Patrick AugustijnsAbstract:ABSTRACT This study aimed to assess the pharmaceutical performance of formulations consisting of either indomethacin or glibenclamide and the Ordered Mesoporous Silica material SBA‐15. Both compounds were loaded on SBA‐15 via solvent impregnation. Adsorption in the SBA‐15 mesopores was confirmed using nitrogen physisorption. Differential scanning calorimetry results suggested that both compounds were dispersed monomolecularly onto the SBA‐15 surface. In in vitro experiments simulating the gastric‐to‐intestinal transition, the release of both compounds from SBA‐15 remained under 1% in simulated gastric fluid (SGF, pH 1.2), whereas both drugs were completely released within 10 min after transfer to fasted state simulated intestinal fluid (FaSSIF, pH 6.5). As both drugs exhibited very rapid precipitation from the supersaturated state in SGF, the preferential release in FaSSIF—where conditions are more favourable by virtue of either much higher solubility (indomethacin) or more stable supersaturation (glibenclamide)—was considered crucial towards achieving optimal absorption. This hypothesis was confirmed by an in vivo study, where the extent of absorption of a glibenclamide–SBA‐15 formulation was found to be more than fourfold higher than that of the commercial glibenclamide product Daonil®. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4864–4876, 2011
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Molecular organization of hydrophobic molecules and co-adsorbed water in SBA-15 Ordered Mesoporous Silica material
Phys. Chem. Chem. Phys., 2011Co-Authors: Randy Mellaerts, Jasper Jammaer, Patrick Augustijns, Michiel Van Speybroeck, Guy Van Den Mooter, Maarten B. J. Roeffaers, Kristof Houthoofd, Gert De Cremer, Johan Hofkens, Johan A. MartensAbstract:The purpose of this study was to improve our understanding of the molecular organization of hydrophobic guest molecules in the presence of co-adsorbed water inside SBA-15 Ordered Mesoporous Silica material. Understanding this adsorption competition is essential in the development of applications of controlled adsorption and desorption. The poorly water soluble drug compound itraconazole and the fluorescent probe Nile red were selected for the study. The interaction between itraconazole and SBA-15 was investigated using FT-IR, 1H MAS NMR and 29Si MAS NMR spectroscopy, by determination of adsorption isotherms and release kinetics in simulated gastric fluid. The distribution and migration of the hydrophobic fluorescent probe Nile red was visualized in situ using confocal fluorescence microscopy. For both molecules, there was a pronounced influence of the co-adsorbed water on adsorption, hydrophobic aggregation and migration in SBA-15 pores. These insights contribute to the development of practical methods for loading Ordered Mesoporous Silica materials with hydrophobic molecules.
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enhanced absorption of the poorly soluble drug fenofibrate by tuning its release rate from Ordered Mesoporous Silica
European Journal of Pharmaceutical Sciences, 2010Co-Authors: Michiel Van Speybroeck, Raf Mols, Jan Van Humbeeck, Pieter Annaert, Randy Mellaerts, Guy Van Den Mooter, Johan A. Martens, Patrick AugustijnsAbstract:Abstract The aim of the present study was to evaluate the effect of release rate from Ordered Mesoporous Silica materials on the rate and extent of absorption of the poorly soluble drug fenofibrate. Three Ordered Mesoporous Silica materials with different pore diameter (7.3 nm, 4.4 nm and 2.7 nm) were synthesized and loaded with fenofibrate via impregnation. Release experiments were conducted under sink conditions and under supersaturating conditions in biorelevant media, simulating the fasted and the fed state. Subsequently, all Silica-based formulations were evaluated in vivo (rat model). The release experiments under sink conditions indicated a clear increase in release rate with increasing pore size. However, under supersaturating conditions (FaSSIF), the, pharmaceutical performance (in terms of both the degree and duration of supersaturation), increased with decreasing pore size. The same trend was observed in vivo (fasted state): the area under the plasma concentration–time profile amounted to 102 ± 34 μM h, 86 ± 19 μM h and 20 ± 13 μM h for the materials with pore diameter of 2.7 nm, 4.4 nm and 7.3 nm, respectively. The results of this, study demonstrate that a decrease in drug release rate – and thus, a decrease of the rate at which supersaturation is created – is beneficial to the absorption of fenofibrate.
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physical state of poorly water soluble therapeutic molecules loaded into sba 15 Ordered Mesoporous Silica carriers a case study with itraconazole and ibuprofen
Langmuir, 2008Co-Authors: Randy Mellaerts, Jasper Jammaer, Michiel Van Speybroeck, Jan Van Humbeeck, Guy Van Den Mooter, Patrick Augustijns, Hong Chen, Johan A. MartensAbstract:The Ordered Mesoporous Silica material SBA-15 was loaded with the model drugs itraconazole and ibuprofen using three different procedures: (i) adsorption from solution, (ii) incipient wetness impregnation, and (iii) heating of a mixture of drug and SBA-15 powder. The location of the drug molecules in the SBA-15 particles and molecular interactions were investigated using nitrogen adsorption, TGA, DSC, DRS UV−vis, and XPS. The in vitro release of hydrophobic model drugs was evaluated in an aqueous environment simulating gastric fluid. The effectiveness of the loading method was found to be strongly compound dependent. Incipient wetness impregnation using a concentrated itraconazole solution in dichloromethane followed by solvent evaporation was most efficient for dispersing itraconazole in SBA-15. The itraconazole molecules were located on the mesopore walls and inside micropores of the mesopore walls. When SBA-15 was loaded by slurrying it in a diluted itraconazole solution from which the solvent was evap...
Patrick Augustijns - One of the best experts on this subject based on the ideXlab platform.
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In situ FT-IR investigation of etravirine speciation in pores of SBA-15 Ordered Mesoporous Silica material upon contact with water.
Molecular Pharmaceutics, 2013Co-Authors: Randy Mellaerts, Patrick Augustijns, Guy Van Den Mooter, Elie J. Fayad, Mickaël Rivallan, Frédéric Thibault-starzyk, Johan A. MartensAbstract:Ordered Mesoporous Silica (OMS) has been recognized as promising adsorbent material for drug molecules with low aqueous solubility. The release of drug molecules from OMS upon contact with aqueous ...
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preventing release in the acidic environment of the stomach via occlusion in Ordered Mesoporous Silica enhances the absorption of poorly soluble weakly acidic drugs
Journal of Pharmaceutical Sciences, 2011Co-Authors: Michiel Van Speybroeck, Jan Van Humbeeck, Pieter Annaert, Randy Mellaerts, Guy Van Den Mooter, Johan A. Martens, Patrick AugustijnsAbstract:ABSTRACT This study aimed to assess the pharmaceutical performance of formulations consisting of either indomethacin or glibenclamide and the Ordered Mesoporous Silica material SBA‐15. Both compounds were loaded on SBA‐15 via solvent impregnation. Adsorption in the SBA‐15 mesopores was confirmed using nitrogen physisorption. Differential scanning calorimetry results suggested that both compounds were dispersed monomolecularly onto the SBA‐15 surface. In in vitro experiments simulating the gastric‐to‐intestinal transition, the release of both compounds from SBA‐15 remained under 1% in simulated gastric fluid (SGF, pH 1.2), whereas both drugs were completely released within 10 min after transfer to fasted state simulated intestinal fluid (FaSSIF, pH 6.5). As both drugs exhibited very rapid precipitation from the supersaturated state in SGF, the preferential release in FaSSIF—where conditions are more favourable by virtue of either much higher solubility (indomethacin) or more stable supersaturation (glibenclamide)—was considered crucial towards achieving optimal absorption. This hypothesis was confirmed by an in vivo study, where the extent of absorption of a glibenclamide–SBA‐15 formulation was found to be more than fourfold higher than that of the commercial glibenclamide product Daonil®. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4864–4876, 2011
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Molecular organization of hydrophobic molecules and co-adsorbed water in SBA-15 Ordered Mesoporous Silica material
Phys. Chem. Chem. Phys., 2011Co-Authors: Randy Mellaerts, Jasper Jammaer, Patrick Augustijns, Michiel Van Speybroeck, Guy Van Den Mooter, Maarten B. J. Roeffaers, Kristof Houthoofd, Gert De Cremer, Johan Hofkens, Johan A. MartensAbstract:The purpose of this study was to improve our understanding of the molecular organization of hydrophobic guest molecules in the presence of co-adsorbed water inside SBA-15 Ordered Mesoporous Silica material. Understanding this adsorption competition is essential in the development of applications of controlled adsorption and desorption. The poorly water soluble drug compound itraconazole and the fluorescent probe Nile red were selected for the study. The interaction between itraconazole and SBA-15 was investigated using FT-IR, 1H MAS NMR and 29Si MAS NMR spectroscopy, by determination of adsorption isotherms and release kinetics in simulated gastric fluid. The distribution and migration of the hydrophobic fluorescent probe Nile red was visualized in situ using confocal fluorescence microscopy. For both molecules, there was a pronounced influence of the co-adsorbed water on adsorption, hydrophobic aggregation and migration in SBA-15 pores. These insights contribute to the development of practical methods for loading Ordered Mesoporous Silica materials with hydrophobic molecules.
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enhanced absorption of the poorly soluble drug fenofibrate by tuning its release rate from Ordered Mesoporous Silica
European Journal of Pharmaceutical Sciences, 2010Co-Authors: Michiel Van Speybroeck, Raf Mols, Jan Van Humbeeck, Pieter Annaert, Randy Mellaerts, Guy Van Den Mooter, Johan A. Martens, Patrick AugustijnsAbstract:Abstract The aim of the present study was to evaluate the effect of release rate from Ordered Mesoporous Silica materials on the rate and extent of absorption of the poorly soluble drug fenofibrate. Three Ordered Mesoporous Silica materials with different pore diameter (7.3 nm, 4.4 nm and 2.7 nm) were synthesized and loaded with fenofibrate via impregnation. Release experiments were conducted under sink conditions and under supersaturating conditions in biorelevant media, simulating the fasted and the fed state. Subsequently, all Silica-based formulations were evaluated in vivo (rat model). The release experiments under sink conditions indicated a clear increase in release rate with increasing pore size. However, under supersaturating conditions (FaSSIF), the, pharmaceutical performance (in terms of both the degree and duration of supersaturation), increased with decreasing pore size. The same trend was observed in vivo (fasted state): the area under the plasma concentration–time profile amounted to 102 ± 34 μM h, 86 ± 19 μM h and 20 ± 13 μM h for the materials with pore diameter of 2.7 nm, 4.4 nm and 7.3 nm, respectively. The results of this, study demonstrate that a decrease in drug release rate – and thus, a decrease of the rate at which supersaturation is created – is beneficial to the absorption of fenofibrate.
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physical state of poorly water soluble therapeutic molecules loaded into sba 15 Ordered Mesoporous Silica carriers a case study with itraconazole and ibuprofen
Langmuir, 2008Co-Authors: Randy Mellaerts, Jasper Jammaer, Michiel Van Speybroeck, Jan Van Humbeeck, Guy Van Den Mooter, Patrick Augustijns, Hong Chen, Johan A. MartensAbstract:The Ordered Mesoporous Silica material SBA-15 was loaded with the model drugs itraconazole and ibuprofen using three different procedures: (i) adsorption from solution, (ii) incipient wetness impregnation, and (iii) heating of a mixture of drug and SBA-15 powder. The location of the drug molecules in the SBA-15 particles and molecular interactions were investigated using nitrogen adsorption, TGA, DSC, DRS UV−vis, and XPS. The in vitro release of hydrophobic model drugs was evaluated in an aqueous environment simulating gastric fluid. The effectiveness of the loading method was found to be strongly compound dependent. Incipient wetness impregnation using a concentrated itraconazole solution in dichloromethane followed by solvent evaporation was most efficient for dispersing itraconazole in SBA-15. The itraconazole molecules were located on the mesopore walls and inside micropores of the mesopore walls. When SBA-15 was loaded by slurrying it in a diluted itraconazole solution from which the solvent was evap...
Dahui Chen - One of the best experts on this subject based on the ideXlab platform.
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separation and preconcentration of inorganic arsenic species in natural water samples with 3 2 aminoethylamino propyltrimethoxysilane modified Ordered Mesoporous Silica micro column and their determination by inductively coupled plasma optical emissi
Journal of Hazardous Materials, 2009Co-Authors: Dahui Chen, Chaozhang HuangAbstract:Abstract A simple and sensitive method using micro-column packed with 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) modified Ordered Mesoporous Silica combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for the speciation of inorganic arsenic (As(III) and As(V)) has been developed. The adsorption behaviors of As(III) and As(V) on AAPTS modified Ordered Mesoporous Silica were investigated. It was found that As(V) can be selectively adsorbed on the micro-column within pH of 3–9, while As(III) could not be retained in the studied pH range and passed through the micro-column directly. Total inorganic arsenic was extracted after the oxidation of As(III) to As(V) with 50.0 μmol L−1 KMnO4. The assay of As(III) was based on subtracting As(V) from total As. The effect of various parameters on the separation/preconcentration of As(III) and As(V) have been investigated and the optimal experimental conditions were established. The adsorption capacity of AAPTS modified Ordered Mesoporous Silica for As(V) was found to be 10.3 mg g−1. The detection limit of the method for As(V) was 0.05 μg L−1 with an enrichment factor of 100, and the relative standard deviation (R.S.D.) was 5.7% (n = 7, C = 1.0 μg L−1). In order to validate the developed method, a certified reference material GSBZ50004-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of inorganic arsenic in natural water samples.
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chitosan modified Ordered Mesoporous Silica as micro column packing materials for on line flow injection inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples
Talanta, 2009Co-Authors: Dahui Chen, Chaozhang HuangAbstract:Abstract A novel adsorbent of chitosan chemically modified Ordered Mesoporous Silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target heavy metals such as pH, sample flow rate and volume, eluent concentration and volume, interfering ions were investigated. Under the optimized experimental conditions, an enrichment factor of 20 and sampling frequency of 10 h −1 were obtained. The detection limits of the method for V, Cu, Pb, Cd and Hg were 0.33, 0.30, 0.96, 0.05 and 0.93 ng mL −1 , and the relative standard deviations (RSDs) were 2.8%, 6.7%, 1.8%, 4.0% and 5.3% ( n = 7, C = 10 ng mL −1 ), respectively. The adsorption capacities of chitosan modified Ordered Mesoporous Silica for V, Cu, Pb, Cd, and Hg were found to be 16.3, 21.7, 22.9, 12.2 and 13.5 mg g −1 , respectively. In order to validate the developed method, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method has also been applied to the determination of trace heavy metals in natural water samples with satisfactory results.
Chaozhang Huang - One of the best experts on this subject based on the ideXlab platform.
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separation and preconcentration of inorganic arsenic species in natural water samples with 3 2 aminoethylamino propyltrimethoxysilane modified Ordered Mesoporous Silica micro column and their determination by inductively coupled plasma optical emissi
Journal of Hazardous Materials, 2009Co-Authors: Dahui Chen, Chaozhang HuangAbstract:Abstract A simple and sensitive method using micro-column packed with 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) modified Ordered Mesoporous Silica combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for the speciation of inorganic arsenic (As(III) and As(V)) has been developed. The adsorption behaviors of As(III) and As(V) on AAPTS modified Ordered Mesoporous Silica were investigated. It was found that As(V) can be selectively adsorbed on the micro-column within pH of 3–9, while As(III) could not be retained in the studied pH range and passed through the micro-column directly. Total inorganic arsenic was extracted after the oxidation of As(III) to As(V) with 50.0 μmol L−1 KMnO4. The assay of As(III) was based on subtracting As(V) from total As. The effect of various parameters on the separation/preconcentration of As(III) and As(V) have been investigated and the optimal experimental conditions were established. The adsorption capacity of AAPTS modified Ordered Mesoporous Silica for As(V) was found to be 10.3 mg g−1. The detection limit of the method for As(V) was 0.05 μg L−1 with an enrichment factor of 100, and the relative standard deviation (R.S.D.) was 5.7% (n = 7, C = 1.0 μg L−1). In order to validate the developed method, a certified reference material GSBZ50004-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of inorganic arsenic in natural water samples.
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chitosan modified Ordered Mesoporous Silica as micro column packing materials for on line flow injection inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples
Talanta, 2009Co-Authors: Dahui Chen, Chaozhang HuangAbstract:Abstract A novel adsorbent of chitosan chemically modified Ordered Mesoporous Silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target heavy metals such as pH, sample flow rate and volume, eluent concentration and volume, interfering ions were investigated. Under the optimized experimental conditions, an enrichment factor of 20 and sampling frequency of 10 h −1 were obtained. The detection limits of the method for V, Cu, Pb, Cd and Hg were 0.33, 0.30, 0.96, 0.05 and 0.93 ng mL −1 , and the relative standard deviations (RSDs) were 2.8%, 6.7%, 1.8%, 4.0% and 5.3% ( n = 7, C = 10 ng mL −1 ), respectively. The adsorption capacities of chitosan modified Ordered Mesoporous Silica for V, Cu, Pb, Cd, and Hg were found to be 16.3, 21.7, 22.9, 12.2 and 13.5 mg g −1 , respectively. In order to validate the developed method, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method has also been applied to the determination of trace heavy metals in natural water samples with satisfactory results.