The Experts below are selected from a list of 2859 Experts worldwide ranked by ideXlab platform
J O Ogeto - One of the best experts on this subject based on the ideXlab platform.
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examination of alkaloidal constituents of zanthoxylum usambarense by a combination of ion pair extraction and ion pair chromatography using Sodium Perchlorate
Phytochemical Analysis, 1995Co-Authors: Atsushi Kato, Masataka Moriyasu, Yumi Nishiyama, Momoyo Ichimaru, F D Juma, Joseph N Nganga, Simon G Mathenge, J O OgetoAbstract:Quaternary alkaloids of the stem of Zanthoxylum usambarense, an important medicinal plant in Kenya utilized for the treatment of pneumonia and rheumatism, were examined by a combination of ion-pair extraction and preparative ion-pair high performance liquid chromatography (HPLC), in which Sodium Perchlorate was used as an ion-pair reagent. Quaternary bases were extractable from aqueous solution into 1,2-dichloroethane in the presence of Perchlorate in acidic conditions. The phenomenon is explained in terms of ion-pair extraction between alkaloidal cation and Perchlorate anion. The quaternary alkaloidal fraction thus obtained was well separated by means of ion-pair HPLC in which Sodium Perchlorate was also utilized. Furthermore, the solvent system was easily applied to preparative HPLC, yielding the pure Perchlorate of each alkaloid. Eight quaternary bases in Z. usambarense were thus obtained and their structures were elucidated. One of them was a new quaternary base of the tetrahydroprotoberberine type, which was named (-)-usambarine.
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ion pair and ion suppression high performance liquid chromatographic analysis of alkaloidal constituents of artabotrys monteiroae
Phytochemical Analysis, 1993Co-Authors: Atsushi Kato, Masataka Moriyasu, Yumi Nishiyama, Momoyo Ichimaru, F D Juma, J O OgetoAbstract:Ion-pair and ion-suppression mode high performance liquid chromatography was conducted on the alkaloidal constituents of the roots of Artabotrys monteiroae, an important medicinal plant in Kenya having analgesic and anti-inflammatory action. Use of Sodium Perchlorate as an ion-pair reagent led to excellent separation. In the ion-suppression system containing ammonium acetate, the separation was rather poor, but liquid chromatography-mass spectrometry was possible, which was not the case in the ion-pair system. Four aporphines, (-)-asimilobine, (+)-wilsonirine, (+)-norisoboldine and anonaine, and a benzylisoquinoline, (+)-reticuline, were identified after isolation by preparative thin layer chromatography.
Adam Bald - One of the best experts on this subject based on the ideXlab platform.
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conductance studies of nacl kcl nabr nai nabph4 bu4ni and naclo4 in water 2 butoxyethanol mixtures at t 298 15 k
Journal of Chemical & Engineering Data, 2010Co-Authors: Agnieszka Borun, Anna Florczak, Adam BaldAbstract:The electrical conductances of solutions of Sodium chloride (NaCl), potassium chloride (KCl), Sodium bromide (NaBr), Sodium iodide (NaI), Sodium tetraphenylborate (NaBPh4), tetrabutylammonium iodide (Bu4NI), and Sodium Perchlorate (NaClO4) in water (1) + 2-butoxyethanol (2) mixtures containing (0.01, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.20) mole fractions of 2-butoxyethanol have been measured at T = 298.15 K. The conductance data have been analyzed by the Fuoss−Justice equation. The individual limiting ionic conductivities of Na+, K+, Bu4N+, BPh4−, I−, Cl−, Br−, and ClO4− ions have been determined using the Fuoss−Hirsch assumption. The dependencies of the limiting molar conductances, Λo, and Walden products, Λoη, versus mixed solvent composition have been discussed.
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conductance studies of nacl kcl nabr nai nabph4 bu4ni and naclo4 in water 2 methoxyethanol mixtures at 298 15 k
Journal of Molecular Liquids, 2009Co-Authors: Agnieszka Borun, Anna Florczak, Adam BaldAbstract:Abstract The electrical conductances of the solutions of Sodium chloride (NaCl), potassium chloride (KCl), Sodium bromide (NaBr), Sodium iodide (NaI), Sodium tetraphenylborate (NaBPh 4 ), tetrabutylammonium iodide (Bu 4 NI) and Sodium Perchlorate (NaClO 4 ) in water (1) + 2-methoxyethanol (2) mixtures containing 0.01, 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 mol fractions of 2-methoxyethanol have been reported at 298.15 K. The conductance data have been analyzed by the Fuoss–Justice equation. The individual limiting ionic conductivities of Na + , K + , Bu 4 N + , BPh 4 − , I − , Cl − , and Br − ions have been determined using the Fuoss–Hirsch assumption. The dependencies of the limiting molar conductances, Λ o , and Walden products, Λ o η , versus mixed solvent composition have been discussed.
Guijuan Qiao - One of the best experts on this subject based on the ideXlab platform.
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determination of platinum by ion pair reversed phase high performance liquid chromatography with 4 4 bis dimethylamino thiobenzophenone
Journal of Chromatography A, 1994Co-Authors: Xiaosong Zhang, Guijuan QiaoAbstract:Abstract Platinum (II) was separated and determined by ion-pair reversed-phase high-performance liquid chromatography with spectrophotometric detection at 520 nm. 4,4'-Bis(dimethylamino)thiobenzophenone (TMK) was used as a precolumn complexing agent. The optimum conditions for the separation and determination of the Pt(II)-TMK complex were investigated. The complex was separated on a Nucleosil C18 column (250 mm × 4.0 mm I.D.) with tetrahydrofuran-water (48:52, v v ) containing 0.035 M acetic acid-Sodium acetate buffer (pH 3.5), 0.20 M Sodium Perchlorate and 8.5 · 10−5M TMK. The proposed method was applied to the determination of platinum in cisplatin and carboplatinum samples.
Atsushi Kato - One of the best experts on this subject based on the ideXlab platform.
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examination of alkaloidal constituents of zanthoxylum usambarense by a combination of ion pair extraction and ion pair chromatography using Sodium Perchlorate
Phytochemical Analysis, 1995Co-Authors: Atsushi Kato, Masataka Moriyasu, Yumi Nishiyama, Momoyo Ichimaru, F D Juma, Joseph N Nganga, Simon G Mathenge, J O OgetoAbstract:Quaternary alkaloids of the stem of Zanthoxylum usambarense, an important medicinal plant in Kenya utilized for the treatment of pneumonia and rheumatism, were examined by a combination of ion-pair extraction and preparative ion-pair high performance liquid chromatography (HPLC), in which Sodium Perchlorate was used as an ion-pair reagent. Quaternary bases were extractable from aqueous solution into 1,2-dichloroethane in the presence of Perchlorate in acidic conditions. The phenomenon is explained in terms of ion-pair extraction between alkaloidal cation and Perchlorate anion. The quaternary alkaloidal fraction thus obtained was well separated by means of ion-pair HPLC in which Sodium Perchlorate was also utilized. Furthermore, the solvent system was easily applied to preparative HPLC, yielding the pure Perchlorate of each alkaloid. Eight quaternary bases in Z. usambarense were thus obtained and their structures were elucidated. One of them was a new quaternary base of the tetrahydroprotoberberine type, which was named (-)-usambarine.
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ion pair and ion suppression high performance liquid chromatographic analysis of alkaloidal constituents of artabotrys monteiroae
Phytochemical Analysis, 1993Co-Authors: Atsushi Kato, Masataka Moriyasu, Yumi Nishiyama, Momoyo Ichimaru, F D Juma, J O OgetoAbstract:Ion-pair and ion-suppression mode high performance liquid chromatography was conducted on the alkaloidal constituents of the roots of Artabotrys monteiroae, an important medicinal plant in Kenya having analgesic and anti-inflammatory action. Use of Sodium Perchlorate as an ion-pair reagent led to excellent separation. In the ion-suppression system containing ammonium acetate, the separation was rather poor, but liquid chromatography-mass spectrometry was possible, which was not the case in the ion-pair system. Four aporphines, (-)-asimilobine, (+)-wilsonirine, (+)-norisoboldine and anonaine, and a benzylisoquinoline, (+)-reticuline, were identified after isolation by preparative thin layer chromatography.
Agnieszka Borun - One of the best experts on this subject based on the ideXlab platform.
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conductance studies of nacl kcl nabr nai nabph4 bu4ni and naclo4 in water 2 butoxyethanol mixtures at t 298 15 k
Journal of Chemical & Engineering Data, 2010Co-Authors: Agnieszka Borun, Anna Florczak, Adam BaldAbstract:The electrical conductances of solutions of Sodium chloride (NaCl), potassium chloride (KCl), Sodium bromide (NaBr), Sodium iodide (NaI), Sodium tetraphenylborate (NaBPh4), tetrabutylammonium iodide (Bu4NI), and Sodium Perchlorate (NaClO4) in water (1) + 2-butoxyethanol (2) mixtures containing (0.01, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.20) mole fractions of 2-butoxyethanol have been measured at T = 298.15 K. The conductance data have been analyzed by the Fuoss−Justice equation. The individual limiting ionic conductivities of Na+, K+, Bu4N+, BPh4−, I−, Cl−, Br−, and ClO4− ions have been determined using the Fuoss−Hirsch assumption. The dependencies of the limiting molar conductances, Λo, and Walden products, Λoη, versus mixed solvent composition have been discussed.
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conductance studies of nacl kcl nabr nai nabph4 bu4ni and naclo4 in water 2 methoxyethanol mixtures at 298 15 k
Journal of Molecular Liquids, 2009Co-Authors: Agnieszka Borun, Anna Florczak, Adam BaldAbstract:Abstract The electrical conductances of the solutions of Sodium chloride (NaCl), potassium chloride (KCl), Sodium bromide (NaBr), Sodium iodide (NaI), Sodium tetraphenylborate (NaBPh 4 ), tetrabutylammonium iodide (Bu 4 NI) and Sodium Perchlorate (NaClO 4 ) in water (1) + 2-methoxyethanol (2) mixtures containing 0.01, 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 mol fractions of 2-methoxyethanol have been reported at 298.15 K. The conductance data have been analyzed by the Fuoss–Justice equation. The individual limiting ionic conductivities of Na + , K + , Bu 4 N + , BPh 4 − , I − , Cl − , and Br − ions have been determined using the Fuoss–Hirsch assumption. The dependencies of the limiting molar conductances, Λ o , and Walden products, Λ o η , versus mixed solvent composition have been discussed.