共查询到19条相似文献,搜索用时 171 毫秒
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用甲基乙烯基聚硅氧烷涂敷硅烷化的微粒硅胶,制备出一种新的涂敷型反相高效液相色谱固定相。对 其制备条件及在碱性条件下的稳定性进行了考察,用pH=12的甲醇-水流动相连续使用8000mL后,固定相的色 谱性能仍很好。 相似文献
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表层二氧化锆/硅基-CDMPC手性固定相的制备及联苯双酯类保肝药的直接拆分 总被引:1,自引:0,他引:1
用分子自组装的方法制备了表层纳米氧化锆包覆多孔微米硅球,得到的氧化锆 /硅胶微球用作高效液相色谱担体,本方法制备的担体具有氧化锆的表面特性并保 持了硅胶的颗粒均匀、表面积大、渗透性好的优点,可以制备大涂敷量的手性固定 相,以增加固定相的手性识别能力,以涂敷量为20%的纤维素-三(3,5-二甲基苯 基氨基甲酸酯)-氧化锆/硅胶手性固定相(CDMPC-coated ZrO_2/SiO_2)上,对 联苯双酯类保肝药物进行直接拆分,考察了流动相极性、第二种极性改性剂对样品 保留和拆分的影响;并对手性拆分机理进行了阐述,结果表明:CDMPC- ZrO_2/SiO_2手性固定相比CDMPC-ZrO_2具有更好的手性拆分能力。 相似文献
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合成了纤维素-三和纤维素-三衍生物,并涂敷于自制的球形硅胶上,制备了用于高效液相色谱手性拆分的固定相。考察了涂敷量,流动相等因素对对手性拆分的影响,测定了一个不对称氢化酯化反应的对映体过剩值。 相似文献
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将纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)涂敷于氨丙基硅胶上制备成高效液相色谱(HPLC)手性固定相,对手性农药顺式、反式氯氰菊酯和烯唑醇对映异构体在正相条件下进行了手性拆分。分别以正己烷和石油醚为流动相,考察改性剂的含量;在正己烷流动相条件下考察了色谱柱长度、温度对拆分效果的影响。试验结果显示,改性剂含量的减少、长色谱柱及降低温度均有利于对映体的分离。该手性固定相对顺式、反式氯氰菊酯具有非常强的立体选择性,对烯唑醇也有较好的拆分能力。 相似文献
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模拟生物膜色谱用于预测药物的小肠吸收 总被引:7,自引:0,他引:7
采用涂敷磷脂的硅胶为模拟生物膜色谱固定相,与传统的凝胶体相比固定相的机械强度及磷脂固载能力均有较大提高,且有较好的稳定性。研究发现氢化可的松等6种药物在模拟生物膜色谱上pH5.4、pH7.0及pH7.4三种缓冲环境下的色谱保留值迭加的结果能够与药物的肠吸收指数押送好的拟合,线性相关系数为0.9365,该结果高于单一pH条件下拟合结果,并将此结果与药物在C18反相色谱上的保留值及辛醇-水系统下的分配系数与药物的小肠吸收的拟合结果进行比较,表明与这两种模型相比模拟生物膜色谱预测药物的小肠吸收有更高的准确度。 相似文献
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聚硅氧烷涂敷的反相高效液相色谱固定相 总被引:5,自引:1,他引:5
用甲基乙烯基聚硅氧烷涂敷于硅烷化的微粒硅胶上,制备出一种新型的涂敷型反相高效液相色谱固定相。该固定相对极性、非极性和碱性化合物均有良好的分离能力,峰对称性好。对其恶性循环 了考察,连续使用三个月后,固定相的碳量和色谱性能仍保持不变。 相似文献
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Immobilized artificial membrane chromatography stationary phase was prepared by coating soybean phosphatidylcholine (PC) on zirconia–magnesia micro‐particles. The stability and chromatographic properties were investigated and compared with the PC‐coated silica chromatography stationary phase prepared by the same method. PC‐coated zirconia–magnesia chromatography stationary phase was more stable than the silica especially on resisting organic solvents. Hydrophobic action was the main factor for the retention of analyte on the new artificial membrane chromatography stationary phase, and electrostatic interaction had some contribution to retention. In addition, the special interaction between analyte and matrix affected retention greatly. Basic solutes were appropriate to be analyzed on PC‐coated zirconia–magnesia stationary phase and acidic solutes were appropriate to be done on the silica one. Hence, the two different matrices artificial membrane stationary phases were perfectly complementary. 相似文献
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The novel grafted silica supports were investigated. The anion exchanger was prepared by chemical modification of a bare silica gel surface. The support was coated with a polymeric moiety formed by condensation polymerization of primary amine with diepoxide. The synthesized copolymer of methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDE) exhibited a dendrimer structure. The prepared materials were characterized by elemental analysis, FT-IR spectroscopy and solid state (13)C and (29)Si NMR CP-MAS spectroscopy. The porous structure of the adsorbents was investigated using the low temperature nitrogen adsorption (LTNA) method. It allows determination of the influence of the topology of packing materials on their chromatographic properties. Imaging was also carried out on the surfaces of the synthesized materials by scanning electron microscopy (SEM). The obtained stationary phase was applied in ion chromatography for the separation of inorganic anions (F(-), Cl(-), NO(2)(-), Br(-), NO(3)(-), HPO(4)(2-), SO(4)(2-), ClO(4)(-)). Bicarbonate buffer was used as a mobile phase. 相似文献
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María T. Rodriguez-Estrada Maria F. Caboni Arianna Costa Giovanni Lercker 《Journal of separation science》1998,21(9):509-512
The performance of a fused silica column coated with 50% phenyl-/50% dimethyl-polysiloxane, characterized by a high thermal stability, was evaluated for the gas chromatographic determination of cholesterol oxidation products. A silylated mixture of eighteen oxysterol standards (0.1 mg/ml of each compound) was injected into the gas chromatographic system. The temperature was programmed from 230 to 260°C at 2.5°/min and then to 290°C at 1°/min; the injector and detector temperatures were set at 325°C, and the gas linear velocity was 22.8 cm/s. The column gave a fast (15 min) and satisfactory resolution of the main cholesterol oxides. Good separation of the hydroxy from the epoxy derivatives was achieved.The suitability of the method for the determination of oxysterols in food matrices was successfully tested on a saponified lipid extract from egg yolk powder, previously enriched and purified by NH2 solid phase extraction. 相似文献
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本工作研究了强极性OV-275固定液可以直接涂渍在硅膜改性弹性玻璃毛细管上,研制的柱子具有良好的色谱特性。该柱的柱效,惰性以及热稳定性均优于弹性石英毛细管柱。 相似文献
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A new method for extraction and analysis of ethanol and methanol in human whole blood, urine and saliva samples based on headspace solid phase microextraction (SPME) using silver sulfide (Ag(2)S) and polyvinyl chloride (PVC) coated on silver wire is described. Unlike commercial fibers, which are coated on fused silica, the proposed fiber has a metallic base to which the coating adheres very strongly. Due to metallic base, this fiber is very durable and is thermally stable up to 250 degrees C. After optimization of coating composition and microextraction conditions, the fiber was used for sampling of methanol and ethanol from human body fluids prior to capillary gas chromatographic analysis. The high recovery (>94%), low detection limits (5.6 mg/L for ethanol and 12.8 mg/L for methanol) and excellent linearity (>0.9900) of calibration graphs made the proposed method suitable for this purpose. 相似文献
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锆镁磷脂膜色谱固定相的制备及其在评价药物-膜相互作用中的应用 总被引:1,自引:0,他引:1
基于锆基质与磷脂之间强烈的路易斯酸碱作用,制备了锆镁磷脂膜色谱固定相,并使用红外光谱、X射线光电子能谱对该色谱固定相进行了表征;使用与体内环境类似的生理缓冲液体系为流动相,评价了该模拟生物膜色谱固定相预测药物膜渗透性的能力,结果表明药物在锆镁磷脂膜色谱中的保留(log Kmbm)与表观渗透率(log Papp)在预测药物的膜渗透性、跨膜吸收等方面具有非常好的相关性,相关系数为0.970,斜率接近1。通过理论推导,引入了直观、方便的热力学指标吉布斯自由能差值(Δ(ΔG°))对药物-膜之间的相互作用强弱进行了评价。 相似文献
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T Oshima K Sagara Y Y Tong G Zhang Y H Chen 《Chemical & pharmaceutical bulletin》1989,37(9):2456-2458
A new ion-pair high-performance liquid chromatographic method for the analysis of hyoscyamine and scopolamine in various kinds of crude drugs derived from solanaceous plants was evaluated using sodium dodecyl sulfate as a counter ion. A reversed-phase chromatographic system consisting of a chemically bonded ODS silica gel column with phosphate buffer (pH 2.5)-acetonitrile (65:35) containing 17.5 mM sodium dodecyl sulfate as the mobile phase was used. Hyoscyamine and scopolamine in crude drugs derived from Scopolia, Atropa, Hyoscyamus and Datura species were separated from other compounds in the crude drugs and determined within 20 min after direct injection of the solution extracted with the mobile phase. The results for various kinds of samples are presented. 相似文献
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Summary The characteristic selectivity of unmodified silica using mixed aqueous-methanolic mobile phase systems for the separation
of basic drugs was studied. It was found that low buffer concentration-high methanol eluents show increased chromatographic
performance over mobile phase systems lower in methanol and higher in ion strength. Regarding an assumed ion-exchanger retention
mechanism, the capacity factors of an amino group containing drugs is primarily dependent on the concentration of the cation
and the pH-value of the eluent. By increasing the pH-value of the eluent, elution order of primary and secondary to tertiary
amines is reversed. By only using eluents with buffering capability, a very high stability and reproducibility of retention
of the basic drugs could be observed. Comparing three different brands of unmodified silica materials, with different pore
size and specific surface area, only small differences in the selectivity for the tested drugs could be found. 相似文献