氟草烟异辛酯对映体的手性拆分

利用高效液相色谱手性固定相法对氟草烟异辛酯对映异构体进行了拆分研究。使用了正己烷和石油醚两种流动相体系,正己烷流动相条件下考察了多种极性改性剂及其含量,以及温度对手性拆分的影响。实验结果显示,以异丙醇为改性剂,在正己烷体系中的分离效果最好,室温下最大分离因子可达到1．2,温度降低有利于对映体的拆分。石油醚体系的分离效果不佳。     

乙氧呋草黄对映体的手性拆分研究

进行了除草剂乙氧呋草黄对映体在自制的纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)高效液相色谱手性柱上的拆分研究。使用了两种流动相体系:正己烷-异丙醇;石油醚-异丙醇,并分别考察了流动相中加入的极性改性剂对手性拆分的影响。试验结果显示,乙氧呋草黄在两种流动相体系中都能得到最好的拆分,但正己烷体系优于石油醚体系,流动相中的极性改性剂的含量减少有利于手性拆分。在正己烷流动相条件下考察了柱长、温度对手性拆分的影响。对对映体的拆分机理进行了讨论。     

乙草胺对映体的手性识别

乙草胺对映异构体在纤维素衍生物手性固定相上得到了分离,分离系统为高效液相色谱,流动相为正己烷和石油醚,流动相中添加了乙醇、内醇、异丙醇和丁醇为极性改性剂,考察了各种改性剂及其含量对拆分的影响。在0℃～25℃范围内研究了温度对拆分的影响。试验结果显示,丙醇和丁醇在2％～15％含量范围内对乙草胺没有分离效果,乙醇和异丙醇有一定的分离效果。流动相中醇含量的减少及温度的降低有利于对映体的拆分,在异丙醇含量为2％,温度为0℃时有最佳的分离效果,分离因子为1.20。     

纤维素-三(3,5-二甲基苯基氨基甲酸酯)对烯唑醇对映体的直接拆分

制备了纤维素-三(3，5-二甲基苯基氨基甲酸酯)手性固定相(CDMPC)，以正己烷为流动相，添加异丙醇为改性剂，在高效液相色谱上实现了对烯唑醇光学异构体的直接拆分，探讨了改性剂的含量及色谱柱长对拆分效果的影响，从而优化了拆分条件。试验结果显示，流动相中异丙醇含量的减少有利于对映体的拆分，但保留增强；长色谱柱也有利于对映体的分离。使用两色谱柱串连，当流动相中正己烷与异丙醇的比例为95：5时可达到最佳分离效果，分离因子为1．17。     

植物生长调节剂多效唑的手性分离

使用直链淀粉衍生物涂敷型手性固定相对植物生长调节剂多效唑对映异构体进行了高效液相色谱手性拆分,正己烷分别添加了乙醇、丙醇、异丙醇、丁醇和异丁醇作为流动相,考察了醇含量对拆分的影响。圆二色(CD)检测器确定了对映体的出峰顺序并测定了圆二色特性。多效唑两对映体在V正己烷∶V异丙醇=95∶5流动相条件下可以实现完全分离,分离度达1.63。230nm波长下,出峰顺序为 /-,波长超过238nm,多效唑两对映体无圆二色吸收。     

戊唑醇对映体在直链淀粉衍生物手性固定相上的拆分

利用三[(s)-α-甲基苯基氨基甲酸]直链淀粉酯涂敷型手性固定相高效液相色谱对戊唑醇对映体成功进行拆分.考察了流动相中醇改性剂种类和体积分数对手性拆分的影响.实验结果表明,当流动相中改性剂异丙醇和乙醇体积分数为2%时,戊唑醇获得最大分离度3.90和5.76.同时还考察了分离温度对手性拆分的影响,结果显示分离度随温度升高呈降低趋势.     

高效液相色谱纤维素类手性固定相对外消旋稻丰散的拆分

合成了纤维素-三(3，5-二甲基苯基氨基甲酸酯)手性固定相，制备了手性色谱柱，以正己烷为流动相，添加异丙醇为改性剂，在高效液相色谱上实现了对手性农药稻丰散光学异构体的直接拆分；系统摸索了异丙醇含量、色潜柱长度、流速及温度对拆分效果的影响，优化了拆分条件。结果显示，色谱柱长度对该化合物的拆分影响较大；流动桕巾异丙醇含量的减少以及流速减慢均有利丁对映体的拆分，但也导致保留增强；在5℃．40℃范刚内，温度升高分离度减小。使用长色谱柱，选择适温20℃，调整流动相中正己烷与异丙醇的比例为99．5：0.5(v／v)，流速为0．5ml／min时，可达到最佳分离效果，分离因子为1．38。     

茚虫威在直链淀粉手性固定相上的对映体分离研究

茚虫威对映异构体在三[(S)-α-甲基苯基氨基甲酸]直链淀粉酯涂敷型高效液相色谱手性固定相上成功的获得了拆分.通过考察流动相中醇类改性剂种类和浓度对其对映体分离的影响,优化了色谱分离条件.结果显示:随着流动相中异丙醇和乙醇改性剂含量增加,分离度逐渐变小,当异丙醇和乙醇的含量分别为20%时,茚虫威即可达到基线分离,分离度为1.8和1.25;两种改性剂比较,乙醇比异丙醇有更高的改性效率.同时考察了分离温度对茚虫威手性分离的影响,结果表明,在15～35℃范围内,温度升高和分离度增大呈正相关关系.     

乳氟禾草灵对映体分离及手性拆分热力学研究

以正己烷-异丙醇为流动相,在直链淀粉-三[（S）-α-甲苯基氨基]甲酸酯涂敷型手性固定相上,对乳氟禾草灵R、S对映体进行分离,考察了流动相组成、柱温对其保留和分离的影响;对乳氟禾草灵对映体与固定相之间的保留和分离的热力学机理进行了讨论。实验结果表明,柱温为25℃、正己烷-异丙醇（体积比为90：10）为流动相、流速为0.6mL/min时乳氟禾草灵两对映体得到基线分离。分离温度在25℃～40℃内,两对映体的lnα与1/T呈线性关系,手性拆分过程受焓的控制。     

HPLC手性固定相法拆分手性药物中间体苄基缩水甘油醚

在 Chiralcel OD多糖类手性固定相上 ,以各种不同配比的正己烷 -异丙醇为洗脱剂 ,对苄基缩水甘油醚的外消旋体进行对映体拆分 ,考察了不同洗脱剂配比、柱温和流速对分离度和出峰时间的影响。结果表明 ,手性拆分因子随流动相中强极性组分浓度的增加和柱温的升高而降低 ,流速对拆分因子的影响较小 ,得到了拆分苄基缩水甘油醚的最佳色谱条件     

高效液相色谱直接光学拆分手性农药(英文)

Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k’) and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.     

西酞普兰对映体的手性色谱拆分及吸附平衡

以添加醇类和二乙胺的正己烷为流动相,考察了多糖类、酒石酸类和环糊精类手性固定相对西酞普兰外消旋体的拆分效果,优选合适的手性固定相、流动相和温度等色谱条件,在此基础上利用前沿色谱法测定了西酞普兰对映体的吸附等温线。优化的色谱操作条件为：Chiralpak AD-H柱为固定相,正己烷∶异丙醇∶二乙胺（95∶5∶0.1,体积比）为流动相,柱温35℃。西酞普兰对映体的吸附等温线为优惠型,采用Langmuir方程拟合,效果较好。本研究为模拟移动床（SMB）制备西酞普兰对映体提供重要的基础数据。     

Determination of oxygenates in gasoline by FTIR

Oxygenates of the type C₁ to C₄ alcohols and MTBE have been used for improving the octane number of gasoline and helping in reduction of emissions. These oxygenates are used as substitutes for the poisonous tetraethyl lead. The ASTM D-4815 method utilizes a GC method for determining methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol (2-methyl-1-propanol), tert-butanol (2-methyl-2-propanol) and methyl tert-butyl ether (MTBE) in gasoline. However, since this method requires a variety of column switching and back-flushing systems, the possibility of using a simple and fast mid-IR transmission method for accomplishing the same task was pursued. For this, an instrument manufacturer's software that utilizes a partial least square (PLS) regression analysis in the region of importance for alcohols and ethers (1300 to 810 cm⁻¹) was chosen and successfully developed. A set of fuel blend samples (32) that contained concentrations in the range of 0.7 to 4.0 (wt/vol) of the components were used for calibration purposes. Results indicated that the correlation (R²) between the actual and predicted values of 70 laboratory prepared samples of concentrations in the range 0.7 to 8.1% (wt/vol) were 0.995, 0.995, 0.991, 0.992, 0.983, 0.995, 0.989, 0.984 and 0.996 for methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol and MTBE respectively.     

安息香及其类似物在苯基甘氨酸型手性固定相上的拆分

正相模式下研究了安息香、氢化安息香及α-苯乙醇在苯基甘氨酸型手性固定相Ch irex 3001上的拆分,探讨了流动相组成及柱温对手性拆分效果的影响。当流动相为正己烷∶1,2-二氯乙烷∶乙醇(体积比)=83.5∶15∶1.5,流速为1.0 mL/m in,柱温为25℃时,三者的分离因子分别为1.04、1.11和1.02。此方法可用于氢化安息香等光学纯度的测定。     

Improvement in the gas chromatographic resolution of petroselinate from oleate

In the extraction of oils from seeds of the genus Coriandrum, GC separations of petroselinate from oleate often gave poor resolution of these two isomers. Oleic and petroselinic acids were esterified with a series of alcohols (methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 3-methyl-1-butanol, and 2-ethyl-1-hexanol). GC resolution of the Δ6 from the Δ9 and Δ11 octadecenoates was examined for all ester derivatives on a polar phase column. The Δ6 and Δ9 isomers were unresolved as methyl esters; however, the 2-ethyl-1-hexyl esters gave baseline separation of all three isomers under temperature programming conditions. When isothermal conditions were optimized for each ester, separation of these isomers was possible with good resolution values (>89%) for all the alcohols except methanol, which had a partial resolution of 51%. The rates of esterification of all the alcohols were determined for reactions with both oleic acid and triolein using potassium hydroxide as the esterification catalyst. Methanol gave the largest rate constant in both acid and oil esterification reactions with a rate constant 10-fold better than all of the other alcohols. Based on rates of reaction, resolution of petroselinate from oleate, and removal of residual alcohol, the ethyl ester derivative appears to be the best choice for seed oils containing petroselinic acid.     

100g/L噁草酸乳油高效液相色谱分析方法研究

采用高效液相色谱法,以正己烷+异丙醇为流动相,用CHIRALPAK–IC手性色谱柱和二极管阵列检测器,在230 nm波长下对100 g/L草酸乳油进行定量分析。结果表明,草酸的线性相关系数为0.9999,标准偏差为0.60,变异系数为0.59%,平均回收率为99.94%。     

高效液相色谱-蒸发光散射检测法分析蛋黄磷脂酰胆碱(英文)

Egg yolk phosphatidylcholine(EYPC) is being widely used in food and pharmaceutical industries nowadays owing to its surface activity,pharmaceutical usefulness,and so on.Common determination methods of phospholipids were based on the American Oil Chemists’ Society(AOCS) Official Method Ja7b-91,in which n-hexane/2-propanol/acetate buffer was used as the mobile phase.In order to achieve desired results,gradient elu-tion or buffer solution was used,which made the detection process more complicated.Moreover,water or buffer solution could affect the silica gel column both on its lifespan and the separation efficiency significantly.In this study,different mobile phase and detector were used to simplify EYPC analyzing process instead of using water within the mobile phase.The optimized HPLC operating conditions are as follows:pure methanol as a mobile phase,flow rate of 1.0 ml·min-1,silica gel column(250 mm×4.6 mm,5 μm,Inertsil GLTM),column temperature 30 ℃ and low temperature evaporative light scattering detector(40 ℃,0.35 MPa) as used.Under this optimal condition,the linear relative coefficient of the standard curve is 0.998 and the recovery was in the range of 96.83%-101.58% with a relative standard deviation of 1.79%(n=6).