亲水相互作用色谱柱串联C18柱高效分析饮品中的胭脂红

建立了亲水相互作用色谱柱(HILIC)串联C18柱的方法,高效分离实际样品中的胭脂红,并对色谱柱的串联顺序以及色谱分离条件进行优化。结果表明:当HILIC柱在前C18柱在后,流动相为乙腈-乙酸铵(5 mmol/L)=91∶9(V/V),流速为0.9 mL/min,柱温为25℃,检测波长为508 nm时,此时胭脂红的分离效果最佳。在最佳的色谱分离条件下,选用两种市售饮品进行实际样品的测定,回收率在81.2%~119%。方法适用于水相样品中的强极性物质的高效分离与分析。     

二氢麦角碱在极性嵌入反相色谱固定相上的分离行为

二氢麦角碱的4种组分具有不同的药效特性,需适当的分析方法对其在不同剂型药品中的含量进行分析.传统液相色谱方法使用强碱性流动相,严重腐蚀硅胶基质色谱填料,影响色谱柱寿命.合成了极性嵌入反相固定相--C18酰胺固定相,并在中性流动相条件下分离4种组分.考察了流动相组成和pH对二氢麦角碱在C18酰胺固定相上保留行为的影响.在150 mm×4.6 mm I.D.的C18酰胺色谱柱上,流动相为乙腈-20 mmol/L Na2HPO4(30:70,V/V,pH 7.0)的条件下实现了4种组分的基线分离.与传统方法相比,极性嵌入反相固定相可以有效的改善碱性化合物的分离特性和大幅度地延长色谱柱的使用寿命.     

高效液相色谱-串联质谱法结合多糖衍生物手性固定相拆分氰戊菊酯

建立了以多糖衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分氰戊菊酯对映体的方法。在反相液相色谱条件下,考察了手性固定相的种类、流动相组成、柱温、流速对氰戊菊酯4个立体异构体分离的影响。同时,利用热力学方法对氰戊菊酯的立体异构体与固定相之间的色谱保留和分离的热力学机理进行了探讨。结果表明:采用Lux Cellulose-3(纤维素-三(4-甲基苯甲酸酯))手性色谱柱,在以流动相为乙腈-水(5 mmol/L甲酸铵)=(55:45,V:V)流速0.4 mL/min,柱温30℃的条件下,可在14 mins内实现氰戊菊酯4个立体异构体的基线分离。拓展了HPLC-MS/MS在菊酯类手性农药对映体分离及检测上的应用。     

用反相离子对色谱-蒸发光散射检测法研究阿仑膦酸钠及其相关物质的分离

采用反相离子对色谱-蒸发光散射检测法,研究了阿仑膦酸钠及相关物质的色谱分离。选择的色谱条件是:固定相为Intersil C8(150×4.6 mm i.d.,5μm)柱,以52mmol.L-1正戊胺水溶液(用乙酸调节pH至7.0)-甲醇(98∶2,V/V)为流动相,流速为1.0 mL.min-1,柱温为室温。在该色谱条件下,阿仑膦酸钠与其有关物质(包括合成过程中残余的原料4-氨基丁酸、亚磷酸及分解产物磷酸盐)分离良好。本法简便、快速,为阿仑膦酸钠的常规分析及质量控制提供了一种可靠而有效的手段。     

某些酚类的高温液相色谱行为

建立了高温液相色谱系统,在高温条件下,采用甲醇-水作为流动相,在Polymerx RP-1聚合物(PSDVB)色谱柱上考察了6种酚类样品的色谱行为.实验条件:温度40～160 ℃,流速0.2～5.5 mL/min,流动相中甲醇浓度范围40%～80%.考察了温度、流速和流动相组成对酚类样品的保留、分辨、柱效和系统压力的影响,探讨了酚类样品在聚合物柱上的热力学行为.温度升高2.35℃大约相当于流动相中甲醇浓度增加1%,可以通过改变色谱柱温度调节样品保留和改变选择性.柱温升高,降低了流动相的粘度,允许在高温条件下使用较高的流速实现快速分离.在160℃、V(甲醇):V(水)=40:60,为流动相和3 mL/min流速条件下,可于2.5 min内实现6种酚类的完全分离.     

离子液体作高效液相色谱流动相添加剂分离测定芳香胺

建立了以离子液体作反相高效液相色谱流动相添加剂分离测定邻苯二胺、苯胺和对甲苯胺3种芳香胺的方法。实验以C18反相色谱柱为分离柱,采用紫外检测方法,考察了检测波长、甲醇含量、咪唑离子液体烷基链长度、离子液体溶液浓度等条件对分离和测定的影响,并与其它分离测定芳香胺的方法进行了比较。优化的色谱条件为:以甲醇/1-丁基-3-甲基咪唑四氟硼酸盐水溶液(3.0mmol/L,乙酸调节pH 3.5)=30/70(V/V)为流动相;检测波长254 nm;流速1.0mL/min;柱温30℃。在此条件下,3种芳香胺达到基线分离,在6.5 min之内分离完全;在1～40 mg/L范围内,线性回归方程的相关系数达到0.99以上;检出限为0.07～0.41 mg/L。将本方法应用于废水的测定,加标回收率在92.3%～96.7%之间,相对标准偏差小于3.5%。     

直链淀粉手性固定相拆分富马酸比索洛尔对映体

建立并优化了高效液相色谱手性固定相分离富马酸比索洛尔对映体的方法。使用直链淀粉手性固定相(Chiralpak AD-H柱)在正相条件下拆分了富马酸比索洛尔对映体,考察了达到最佳分离效果时,流动相中极性调节剂的组分、流动相中三乙胺的体积分数以及柱温对富马酸比索洛尔对映体拆分影响。流动相为正己烷/乙醇/三乙胺(90/10/0.1,V/V/V),流速1.0 mL/min,紫外检测波长270 nm,柱温30℃时,两种异构体能达到较好的基线分离,并且不对称合成的(S)-富马酸比索洛尔和(R)-富马酸比索洛尔两种异构体产品,对映体过量(e.e.)均高于99.0%,在此色谱条件下的色谱图峰形良好。方法可广泛用于跟踪手性比索洛尔富马酸盐的合成过程分析和质量控制。     

聚合物基质高效液相色谱填料在白细胞介素-2分离中的应用

聚合物型苯乙烯-二乙烯基苯(PS-DVB)微球装填的麦科菲反相高效液相色谱柱(MKF-RP-HPLC),用于白细胞介素-2(IL-2)分离的最佳色谱条件:流动相A:0.1%三氟乙酸,流动相B:80%乙腈 0.1%三氟乙酸.B液在30 min内从0%线性增大至100%,流速1.0 mL/min;检测波长:280 nm.在该色谱条件下进行系统性实验,结果表明:MKF-RP色谱柱分离IL-2的柱效、分离度、重复性和拖尾因子均能达到药典要求,且柱效和分离度与SOURCE色谱柱相当;MKF-RP色谱柱的pH适用范围为1～14;柱压与SOURCE色谱柱相当,且低于Hypersil C8色谱柱和Polaris C18色谱柱的柱压,可在更高流速下操作;MKF-RP色谱柱的非极性与SOURCE色谱柱相当;MKF-RP色谱柱的超载性能优于SOURCE色谱柱,其对IL-2进样液的最大载样量为300 μg.     

高效液相色谱法分离和分析喷妥司汀及其异构体

利用高效液相色谱方法在普通Polar-RP柱上成功分离pentostatin的4个异构体。通过考察色谱柱、流动相、温度等对分离度的影响,得到最佳分离条件为:室温下以Phenom enex Synergi Polar-RP色谱柱,采用磷酸氢二钠水溶液(50 mmol,pH 8.8)-甲醇(97∶3,V/V)为流动相;282 nm检测;流速为1.0 mL/m in。结果表明,4个异构体之间均达到基线分离,且保留时间和峰面积的RSD均控制在0.6%以内。pentostatin在0.1~1.0g/L、其异构体在0.5~1.5 mg/L范围内的线性相关系数(R)均大于0.99。在此实验基础上,建立分离纯化Pentostatin的制备色谱条件,以制备色谱法得到的产品纯度达到99.8%,收率达到理论产率的80.2%。     

固相萃取富集-高效液相色谱法测定环境水中多菌灵和噻菌灵

建立了以固相萃取技术富集，高效液相色谱法进行分离和检测多菌灵和噻菌灵2种杀菌剂的方法。环境水中的多菌灵和噻菌灵用3M Empore 6mL C18 Cartridge进行固相萃取。以Hypersil ODS柱为分析柱，优化得到高效液相色谱分离条件：流动相为甲醇-水(50：50，V/V)；流速为0．7mL／min；柱温为55℃；在286nm波长下检测，检出限为0．05mg／L。本法操作简便，灵敏，回收率高。     

葡萄糖苷特异性固相萃取固定相的合成、表征及应用

以马来酰亚胺基修饰凝胶载体,通过β-葡萄糖胺和2-亚氨基硫代烷盐酸盐将作为配基的β-葡萄糖脒连接到载体上,合成了一种葡萄糖苷特异性固相萃取固定相,并对其固相萃取性能进行了表征.该固定相对葡萄糖苷具有特异性识别,并成功用于固相萃取分离葡萄糖苷.     

反相液相色谱中固定相和流动相对柱相比的贡献

依据柱相比的热力学定义和反相液相色谱中溶质的计量置换保留理论(the stoichiometric dispheement heory of solute for retention，SDT-R)，对反相液相色谱中固定相和流动相性质、温度对柱相比的影响进行了研究。结果表明：固定相的种类和配基的疏水性对柱相比影响较大，而流动相中有机溶剂的种类，特别是脂肪酸作为置换剂时，对柱相比的影响更大，而柱相比受温度的影响较小。此外，通过用27种小分子溶质对柱相比的测定，其logI和Z良好的线性关系，进一步证明柱相比是一个与溶质性质无关的常数。     

Morphological studies of a hydrogen-bonded LC polymer obtained by photopolymerization in LC solvents

Anisotropic morphologies and the phase behaviour of a hydrogen-bonded LC polymer obtained by photopolymerization in two kinds of LC solvent are discussed. The hydrogen-bonded LC monomer, 4-(6-acryloyloxyhexyloxy) benzoic acid (A6OBA), was photopolymerized in 4-cyano-4′-hexyloxybiphenyl (6OCB) and in 4-cyano-4′-undecyloxybiphenyl (11OCB), which show a nematic phase and a smectic A phase, respectively. After photo-polymerization, the LC media were removed by extraction and the pure polymer was observed by scanning electron microscopy. SEM images showed that the polymer possessed fibrous morphology with a fibre diameter of a few micrometers, based on polymerization-induced phase separation. The overall geometries reflected typical LC characteristics such as schlieren and focal-conic fan textures. It was found that the hydrogen bond between benzoic acid groups in the monomer was rigid enough to fix the anisotropic phase-separated structure forming during the early stage of phase separation; however, it could not permanently maintain the fibre structure due to dissociation at elevated temperature. X-ray measurements revealed that a well developed layer structure of the hydrogen-bonded mesogen existed in the polymer obtained from the smectic phase of 11OCB, whereas a polymer layer structure could develop only partially from the nematic phase of 6OCB.     

亲水有机相-含盐水两相体系的形成机理与分相能力

亲水有机相-含盐水两相体系的形成机理与分相能力;亲水有机相;含盐水相;两相体系;分相机理;分相能力     

Cholesterol-based dimeric liquid crystals: synthesis,mesomorphic behaviour of frustrated phases and DFT study

Chiral unsymmetrical dimeric liquid crystals consisting of a cholesterol moiety as chiral entity and a substituted salicylidene imine core (with the substituent being butyl or fluoro or chloro group) interconnected through an even methylene spacer have been synthesised and their mesomorphic properties are characterised. All the dimers exhibit enantiotropic mesophases. The butyl homologue exhibited N* phase only, the fluoro- and chloro-substituted compound exhibited frustrated blue phases (BPs), N* phase and SmC* or twisted grain boundary (TGB) phases. The occurrence of a fluid frustrated phase, the BP, in particular, observed in compounds with a polar moiety and bent optimised conformation by density functional theory (DFT) study, indicates the importance of polar structures and bent shape of the compounds. Theoretical calculation was performed in order to study the optimised conformation, polarity and electron density distribution of the synthesised cholesterol derivatives using DFT. Time-dependent density functional theory (TD-DFT) calculation also had been carried out to investigate the absorption spectra and HOMO–LUMO energies. The experimental and theoretical absorption spectra are also presented.     

Preorganised effects of a tetramesogenic supermolecule on supramolecular assembly in the liquid crystalline phases

After preparing a homologous series of tetrameric mesogenic compounds in which two U-shaped molecules were connected via a rigid benzene derivative or a flexible alkyl chain, we investigated their phase transition behaviour using optical microscopy, differential scanning calorimetry and X-ray diffraction analysis. The compounds possessing an alkyl spacer as the central group exhibited nematic and smectic A phases just as the corresponding U-shaped molecule did. The compound possessing a 1,2-benzene unit as the connecting group showed nematic and smectic A phases, although the compound possessing a 1,3-benzene unit exhibited only an anticlinic smectic C phase. Structure–property relations of the liquid crystalline tetramers are interpreted in terms of preorganised effects of the four mesogenic units.     

Oxadiazole-based unsymmetrical chiral liquid crystal dimers: synthesis and mesomorphic properties

The synthesis and liquid crystalline properties of novel chiral Schiff's base dimers containing the 1,3,4-oxadiazole ring are reported. The length of the terminal S-alkyl chain has been varied. All the compounds synthesised were thermally stable and exhibited enantiotropic mesomorphism, showing either SmC*–SmA–TGB–N*–BP or SmC*–SmA phase sequence.     

Time‐Resolved Phase Transitions of the Nanocrystalline Cubic to Submicron Monoclinic Phase in Zirconia

The nanocrystalline cubic, tetragonal, and submicron monoclinic phases of pure zirconia were prepared by thermal decomposition of carbonate and hydroxide precursors. The crystallization and isothermal phase transformations of the oxide were studied using high temperature X‐ray diffraction, X‐ray diffraction and Raman spectra of quenched samples. Cubic zirconia formed first, and then progressively transformed to tetragonal and monoclinic phases at temperatures as low as 320°C. The cubic, tetragonal, and monoclinic phases for ZrO₂ were found to be distinct functions of crystallite size, indicating the nanocrystalline nature of these phases. They were found to exist within critical size ranges of 50 to 140 Å, 100 to 220 Å and 190 to 420 Å (±5 Å), respectively. Thus, as the crystallites grow during annealing, they first transform from cubic to tetragonal and then from tetragonal to monoclinic at critical sizes. The classical Avrami equation for nucleation and growth was applied to the tetragonal to monoclinic phase transition.     

Phase equilibria in the GeSe2-SnTe system

Journal of Thermal Analysis and Calorimetry - The phase diagram of the system GeSe2-SnTe is studied by means of X-ray diffraction, differential thermal and measurements of the microhardness and the...     

Physical properties of two systems with induced antiferroelectric phase

Two ferroelectric three‐ring chiral esters, one with a partially fluorinated alkyl chain and another with a cyano terminal group, were mixed with a structurally similar compound having an alkyl terminal chain. In their mixtures an antiferroelectric phase was induced. The phase behaviour, spontaneous polarisation, tilt angle, smectic layer spacing and helical pitch of both systems were determined. The mechanism of the induction of an antiferroelectric phase is different in both cases, with highly tilted phases in former system and less tilted phases in the latter.