The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Jos Hoogmartens - One of the best experts on this subject based on the ideXlab platform.
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analysis of Metacycline by capillary electrophoresis
Electrophoresis, 2001Co-Authors: Eddy Castellanos Gil, Eugene Roets, Pieter Dehouck, Ann Van Schepdael, Jos HoogmartensAbstract:The development and validation of an optimized capillary electrophoresis method for the determination of Metacycline in the presence of its related substances by capillary electrophoresis is shown. The influence of methanol as organic modifier, buffer pH, buffer concentration, capillary length, column temperature, Triton X-100 and methyl-beta-cyclodextrin was investigated. A central composite design was performed in order to optimize the method. The optimal separation conditions were: uncoated fused-silica capillary (39 cm total length, 31 cm effective length, 50 microm ID); as background electrolyte a solution of 160 mM sodium carbonate and 1 mM EDTA (pH 10.35)/methanol (89:13 v/v); temperature, 15 degrees C; voltage, 12 kV. The method showed good selectivity, repeatability, linearity, and sensitivity. The limits of detection and quantitation are 0.024% and 0.06%, respectively, relative to a 2.5 mg/mL solution. Six commercial samples were analyzed quantitatively.
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isolation of doxycycline 6 epidoxycycline and 2 acetyl 2 decarboxamidoMetacycline from commercial Metacycline by preparative column liquid chromatography on silica gel
Journal of Chromatography A, 1991Co-Authors: Weng Naidong, K Verresen, Roger Busson, Eugene Roets, Jos HoogmartensAbstract:Isolation of doxycycline, 6-epidoxycycline and 2-acetyl-2-decaboxamidoMetacycline from commercial Metacycline was achieved by preparative column liquid chromatography on silica gel, previously impregnated with edetate (EDTA). Careful control of the pH of EDTA allowed fine tuning of the separation. The mobile phases were composed of dichloromethane, methanol and .1 mM EDTA at pH 9.0 or 6.0. Structures were confirmed with nuclear magnetic resonance spectroscopy. The presence of doxycycline and its 6-epimer in commercial Metacycline has not previously been described. The presence of the 2-acetyl derivative was not surprising since analogous 2-acetyl derivatives have been identified in other tetracyclines.
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determination of Metacycline and related substances by column liquid chromatography on poly styrene divinylbenzene
Journal of Chromatography A, 1991Co-Authors: Weng Naidong, K Verresen, Eugene Roets, Jos HoogmartensAbstract:Abstract Isocratic column liquid chromatography on poly(styrene-divinylbenzene) copolymer allowed complete separation of Metacycline, 4-epiMetacycline, oxytetracycline, doxycycline and 6-epidoxycycline. 2-Acetyl-2-decarboxamidoMetacycline was eluted on the tail of Metacycline. The mobile phase was 2-methyl-2-propanol-0.2 M phosphate buffer (pH 9.0)-0.01 M sodium ethylenediaminetetraacetate (pH 9.0)-water (2.5:10:10:77.5, m/v/v/v). The flow-rate was 1.0 ml/min and detection was performed at 254 nm. Official standards were compared and a number of commercial bulk samples and specialties were analysed. 2-Acetyl-2-decarboxamidoMetacycline, 6-epidoxy-cycline and doxycycline were the main impurities, while 4-epiMetacycline and oxytetracycline were minor impurities.
Langxing Chen - One of the best experts on this subject based on the ideXlab platform.
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determination of tetracyclines in food samples by molecularly imprinted monolithic column coupling with high performance liquid chromatography
Talanta, 2009Co-Authors: Xiangli Sun, Yukui Zhang, Langxing ChenAbstract:A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic column was prepared by in situ molecular imprinting technique for the first time, and the optimal synthesis conditions and the selectivity of TC imprinted monolithic column were investigated. The interfering substances in food samples and TCs can be separated successfully on imprinted column. Molecularly imprinted solid phase extraction (MISPE) coupling with C18 column was used to determinate the TCs in milk and honey. The recoveries of this method for six tetracyclines antibiotics such as tetracycline (TC), oxytetracycline (OTC), minocycline (MINO), chlortetracycline (CTC), Metacycline (MTC) and doxycycline (DTC) were investigated, and high recoveries of 73.3-90.6% from milk samples and 62.6-82.3% from honey samples were obtained. A method for determination of TCs at low concentration level in milk and honey samples was successfully developed by using the monolithic column as the precolumn for solid phase extraction of six TCs compounds.
Yukui Zhang - One of the best experts on this subject based on the ideXlab platform.
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determination of tetracyclines in food samples by molecularly imprinted monolithic column coupling with high performance liquid chromatography
Talanta, 2009Co-Authors: Xiangli Sun, Yukui Zhang, Langxing ChenAbstract:A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic column was prepared by in situ molecular imprinting technique for the first time, and the optimal synthesis conditions and the selectivity of TC imprinted monolithic column were investigated. The interfering substances in food samples and TCs can be separated successfully on imprinted column. Molecularly imprinted solid phase extraction (MISPE) coupling with C18 column was used to determinate the TCs in milk and honey. The recoveries of this method for six tetracyclines antibiotics such as tetracycline (TC), oxytetracycline (OTC), minocycline (MINO), chlortetracycline (CTC), Metacycline (MTC) and doxycycline (DTC) were investigated, and high recoveries of 73.3-90.6% from milk samples and 62.6-82.3% from honey samples were obtained. A method for determination of TCs at low concentration level in milk and honey samples was successfully developed by using the monolithic column as the precolumn for solid phase extraction of six TCs compounds.
Xiangli Sun - One of the best experts on this subject based on the ideXlab platform.
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determination of tetracyclines in food samples by molecularly imprinted monolithic column coupling with high performance liquid chromatography
Talanta, 2009Co-Authors: Xiangli Sun, Yukui Zhang, Langxing ChenAbstract:A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic column was prepared by in situ molecular imprinting technique for the first time, and the optimal synthesis conditions and the selectivity of TC imprinted monolithic column were investigated. The interfering substances in food samples and TCs can be separated successfully on imprinted column. Molecularly imprinted solid phase extraction (MISPE) coupling with C18 column was used to determinate the TCs in milk and honey. The recoveries of this method for six tetracyclines antibiotics such as tetracycline (TC), oxytetracycline (OTC), minocycline (MINO), chlortetracycline (CTC), Metacycline (MTC) and doxycycline (DTC) were investigated, and high recoveries of 73.3-90.6% from milk samples and 62.6-82.3% from honey samples were obtained. A method for determination of TCs at low concentration level in milk and honey samples was successfully developed by using the monolithic column as the precolumn for solid phase extraction of six TCs compounds.
Eugene Roets - One of the best experts on this subject based on the ideXlab platform.
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analysis of Metacycline by capillary electrophoresis
Electrophoresis, 2001Co-Authors: Eddy Castellanos Gil, Eugene Roets, Pieter Dehouck, Ann Van Schepdael, Jos HoogmartensAbstract:The development and validation of an optimized capillary electrophoresis method for the determination of Metacycline in the presence of its related substances by capillary electrophoresis is shown. The influence of methanol as organic modifier, buffer pH, buffer concentration, capillary length, column temperature, Triton X-100 and methyl-beta-cyclodextrin was investigated. A central composite design was performed in order to optimize the method. The optimal separation conditions were: uncoated fused-silica capillary (39 cm total length, 31 cm effective length, 50 microm ID); as background electrolyte a solution of 160 mM sodium carbonate and 1 mM EDTA (pH 10.35)/methanol (89:13 v/v); temperature, 15 degrees C; voltage, 12 kV. The method showed good selectivity, repeatability, linearity, and sensitivity. The limits of detection and quantitation are 0.024% and 0.06%, respectively, relative to a 2.5 mg/mL solution. Six commercial samples were analyzed quantitatively.
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isolation of doxycycline 6 epidoxycycline and 2 acetyl 2 decarboxamidoMetacycline from commercial Metacycline by preparative column liquid chromatography on silica gel
Journal of Chromatography A, 1991Co-Authors: Weng Naidong, K Verresen, Roger Busson, Eugene Roets, Jos HoogmartensAbstract:Isolation of doxycycline, 6-epidoxycycline and 2-acetyl-2-decaboxamidoMetacycline from commercial Metacycline was achieved by preparative column liquid chromatography on silica gel, previously impregnated with edetate (EDTA). Careful control of the pH of EDTA allowed fine tuning of the separation. The mobile phases were composed of dichloromethane, methanol and .1 mM EDTA at pH 9.0 or 6.0. Structures were confirmed with nuclear magnetic resonance spectroscopy. The presence of doxycycline and its 6-epimer in commercial Metacycline has not previously been described. The presence of the 2-acetyl derivative was not surprising since analogous 2-acetyl derivatives have been identified in other tetracyclines.
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determination of Metacycline and related substances by column liquid chromatography on poly styrene divinylbenzene
Journal of Chromatography A, 1991Co-Authors: Weng Naidong, K Verresen, Eugene Roets, Jos HoogmartensAbstract:Abstract Isocratic column liquid chromatography on poly(styrene-divinylbenzene) copolymer allowed complete separation of Metacycline, 4-epiMetacycline, oxytetracycline, doxycycline and 6-epidoxycycline. 2-Acetyl-2-decarboxamidoMetacycline was eluted on the tail of Metacycline. The mobile phase was 2-methyl-2-propanol-0.2 M phosphate buffer (pH 9.0)-0.01 M sodium ethylenediaminetetraacetate (pH 9.0)-water (2.5:10:10:77.5, m/v/v/v). The flow-rate was 1.0 ml/min and detection was performed at 254 nm. Official standards were compared and a number of commercial bulk samples and specialties were analysed. 2-Acetyl-2-decarboxamidoMetacycline, 6-epidoxy-cycline and doxycycline were the main impurities, while 4-epiMetacycline and oxytetracycline were minor impurities.