N_(263)-亚硝基-R-盐萃取色谱法分离富集痕量钯

本文介绍以N_(263)~-亚硝基-R-盐的混合物为固定相,以硅胶为载体,萃取色谱法分离富集痕量钯,并用2.5ml 1mol的HClO_4溶液淋洗钯-亚硝基-R-盐的铬合物直接进行比色测定痕量钯。     

N,N（二甲庚基）乙酰胺萃钯机理研究

本文研究了N,N二甲庚基乙酰胺(N_(s03))从氯化物体系中萃取钯的机理。应用等摩尔系列法和斜率法确定萃合物组成为:(CH_3CONR_2H)_2PdCl_4。通过紫外-可见光谱法研究,证实N_(503)萃取钯的机理属阴离子交换反应,其萃取方程式为: 2CH_3CONR_2HCl_((o)) PdCl_4~(2-)(a)?(CH_3CONR_2H)_2PdCl_4(o) 2Cl~-(a)     

萃淋树脂伯胺N1923对钯（Ⅱ）的萃取吸附机理（Ⅱ）

研究了伯胺Ｎ_（１９２３）萃淋树脂在Ｎ_（１９２３）成盐及不成盐时吸附钯的反应机理，通过等摩尔系列法、斜率法、红外光谱及核磁共振谱法对吸萃物的组成及吸萃机理进行了探讨。     

石油亚砜与N,N—二（仲辛基）乙酰胺协同萃淋树脂分离富集金和钯

本文报导了石油亚砜与N,N-二(仲辛基)乙酰胺二元协同萃淋树脂吸萃金和钯的性能。该树脂的饱和吸萃容量为148mg Au/g干树脂。用0.5％硫脲可有效地洗脱柱床上的金和钯。     

钯的萃取化学研究—Ⅰ.季铵盐N263从盐酸介质中萃取钯(Ⅱ)的平衡研究

本文考察了水相酸度、氯离子浓度、起始Pd(Ⅱ)浓度、有机相中萃取剂浓度、添加剂正辛醇含量和体系温度等因素对N₂₆₃-正辛烷从盐酸介质中萃取Pd(Ⅱ)的影响,确定了不同条件下萃合物的组成,计算了萃取反应的平衡常数和ΔH值。     

聚天冬氨酸硅质固定相的研制及应用

D，L-天冬氨酸在浓磷酸的存在下加热聚合生成聚琥珀酰亚胺，此产物能与氨丙基硅胶快速反应生成聚琥珀酰胺硅胶，然后再水解生成聚天冬氨酸硅质固定相．并对反应条件进行了优化、实验表明，聚天冬氨酸固定相对蛋白质有较好的分离能力和选择性．     

Concise synthesis of a pentasaccharide related to the anti-leishmanial triterpenoid saponin isolated from Maesa balansae

Concise synthesis of the glycone part (a pentasaccharide) of the anti-leishmanial triterpenoid saponin isolated from Maesa balansae is reported. A late-stage TEMPO-mediated oxidation of a primary hydroxyl group to carboxylic acid has been achieved under phase-transfer conditions. Glycosylations were performed either by thioglycoside or glycosyl trichloroacetimidate activation using sulfuric acid immobilized on silica (H2SO4-silica) in conjunction with N-iodosuccinimide and alone, respectively. H2SO4-silica was proved to be a better choice as promoter than conventional Lewis acid promoters such as TfOH or TMSOTf.     

Concentration of chlorophenols in water to dialkyated catinonic surfactant-silica gel admicelles

Chlorophenols including monochlorophenol, dichlorophenol, trichlorophenol, tetrachlorophenol, and pentachlorophenol in water were extracted into dialkylated cationic surfactant-silica gel admicelles. The dialkylated cationic surfactants such as didecyldimethylammonium bromide (DC10) and didodedyldimethylammonium bromide (DC12) sorbed on silica gel surfaces to form admicelles at pH 9. Approximately 200mg of DC10 was quantitatively sorbed on 1g of silica gel. The sorption further increased by further addition of DC10. This is in contrast to the fact that the maximum sorption of mono-alkylated cetyltrimethyammonium chloride (CTAC) was only ca. 100mg. Based on the fluorescent spectra of a molecular probe, N-phenyl-1-naphthylamine, DC10- and DC12-silica gel admicelles were more hydrophobic than CTAC-silica gel admicelles. The extents of the extraction of chlorophenols into DC10-silica gel admicelles were greater than those into CTAC-silica gel admicelles. However, the extractions to DC12-silica gel admicelles were insufficient due to leakage of DC12 vesicles. Consequently, DC10-silica gel admicelles were the most adequate for concentrating chlorophenols in water. An admicelle column was prepared by passing aqueous buffer solution of DC10 through a Bond Elut Jr. silica gel solid-phase extraction cartridge. It was successfully applied to the 500-fold concentration of chlorophenols including hydrophilic mono-substituted chlorophenol in water samples prior to their HPLC analysis.     

Capillary electrochromatography with monolithic silica column: I. Preparation of silica monoliths having surface-bound octadecyl moieties and their chromatographic characterization and applications to the separation of neutral and charged species

Monolithic silica columns with surface-bound octadecyl (C18) moieties have been prepared by a sol-gel process in 100 microm ID fused-silica capillaries for reversed-phase capillary electrochromatography of neutral and charged species. The reaction conditions for the preparation of the C18-silica monoliths were optimized for maximum surface coverage with octadecyl moieties in order to maximize retention and selectivity toward neutral and charged solutes with a sufficiently strong electroosmotic flow (> 2 mm/s) to yield rapid analysis time. Furthermore, the effect of the pore-tailoring process on the silica monoliths was performed over a wide range of treatment time with 0.010 M ammonium hydroxide solution in order to determine the optimum time and conditions that yield mesopores of narrow pore size distribution that result in high separation efficiency. Under optimum column fabrication conditions and optimum mobile phase composition and flow velocity, the average separation efficiency reached 160 000 plates/m, a value comparable to that obtained on columns packed with 3 microm C18-silica particles with the advantages of high permeability and virtually no bubble formation. The optimized monolithic C18-silica columns were evaluated for their retention properties toward neutral and charged analytes over a wide range of mobile phase compositions. A series of dimensionless retention parameters were evaluated and correlated to solute polarity and electromigration property. A dimensionless mobility modulus was introduced to describe charged solute migration and interaction behavior with the monolithic C18-silica in a counterflow regime during capillary electrochromatography (CEC )separations. The mobility moduli correlated well with the solute hydrophobic character and its charge-to-mass ratio.