Separation of Biphenyl Nitrile Compounds by Microemulsion Electrokinetic Chromatography with Mixed Surfactants

A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.

Simultaneous Determination of Heroin,Amphetamine and their Basic Impurities and Adulterants Using Microemulsion Electrokinetic Chromatography

Simultaneous separation of 17 species of heroin, amphetamine and their basic impurities and adulterants was conducted within 10 minutes by using capillary microemulsion electrokinetic chromatography. The influences of pH and 1-butanol cosurfactant on the separation were investigated, and 1-butanol was found to be a principal factor to improve separation efficiency.

Separation of Six Pyridoncarboylxic Acid Derivatives by Micellar and Microemulsion Electrokinetic Chromatography

Micellar and microemulsion electrokinetic chromatography (MEKC & MEEKC) separation of six closely structural pyridoncarboylxic acid derivatives were studied and compared Both anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant hexadecyl-trimethyl ammonium bromide: (CTAB) were used to form micellar and microemulsion as pseudostation phases, respectively. The effects of the separation conditions on retention time and selectivity were studied. Good resolutions were obtained in selected systems. indicating that there is markably different selectivity between SDS and CTAB systems.

Separation of Hydrophobic Neutral Compounds by Microemulsion Electrokinetic Chromatography

Microemulsion electrokinetic chromatography (MEEKC) was developed for the separation of hydrophobic neutral compounds. The effects of core phase and co-surfactant on the separations were investigated. Under the selected condition, good resolutions were obtained for the test mixtures. The separation efficiencies were higher than 105 theoretical plates per metre.

Separation of Felted Explosives by Pressurized Microemulsion Electrokinetic Chromatography

A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane -120 mmol/L SDS (sodium dodecyl sulphate) - 900 mmol/L butanol - 10 mmol/L borate at pH 9.4 and a pressure-driven flow of 0.020 mL/min under 1.3 MPa was employed to manipulate the separation. Explosives HMX (1, 3, 5, 7-tetranitro-l, 3, 5, 7-tetrazacyclooctane) and TATB (triamino-trinitrobenzene), which were felted on fluorine rubber F2311 (polytrifluorochlorethylene and polyvinylidene fluoride 1/1 co-polymerization) and F2314 (polytrifluorochlorethylene and polyvinylidene fluoride 4/1 co-polymerization) were well separated with very good peak shapes.

Optimized Separation of Nine Xanthones by Microemulsion Electrokinetic Chromatography

A microemulsion electrokinetic chromatography method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically optimized with respect to pH, composition of microemulsion, addition of cyclodextrins, applied voltage and column temperature. Baseline separation was successfully achieved for the nine xanthones, which was also compared with that by micellar electrokinetic chromatography.

The Retention Behaviors of Benzene and Its Alkyl Homologues in Microemulsion Electrokinetic Chromatography

The retention behaviors of benzene and its alkyl homologues in microemulsion electrokinetic chromatography were investigated in both anionic and cationic surfactant MEEKC systems. The effects of the composition of microemulsion on retention time and selectivity were studied. A good linear relationship was obtained between log k and the carbon number of alkyl chain.

蛋白质的微乳液毛细管电动色谱分离研究

考察了用微乳液毛细管电动色谱 ( MEEKC)分离蛋白质时微乳液组成等不同因素对分离的影响 ,并与胶束电动色谱进行对比 ,探讨了其分离机理 。

毛细管微乳液电动色谱和胶束电动色谱分离冰毒及其麻黄碱杂质的比较

通过毛细管微乳液电动色谱10 m in内同时分离了安非他明、甲基安非他明、4,5-亚甲基二氧基安非他明(MDA)和3-甲氧基-4,5-亚甲基二氧基安非他明(MDMA)4种苯丙胺类毒品及其麻黄碱、伪麻黄碱、甲基麻黄碱、甲基伪麻黄碱、去甲麻黄碱等麻黄生物碱杂质。比较了毛细管微乳液电动色谱和丁醇改进的胶束电动色谱模式对分离的影响,发现正丁醇是影响分离的最主要因素。本方法具有很好的重复性和稳定性,可实现对冰毒及其麻黄生物碱杂质的快速分析和鉴定,相对保留时间和相对峰面积的RSD分别小于1.3%和5.0%,可用于冰毒的实际来源推断。

具有油水分配系数测算功能的中药指纹图谱

建立了一种能同时测算中药中主要成分的油水分配系数Pow的功能化中药指纹图谱。采用微乳液电动色谱,以中药女贞子为例,对运行缓冲液浓度、pH值、十二烷基硫酸钠浓度等参数进行了优化。利用SPSS程序对磺胺等从女贞子中提取的6种标准化合物组分的迁移时间tm与其logPow文献值进行非线性拟合,得到女贞子提取组分的标准方程线性关系良好(r=0.988 0)。在相同的实验条件下测得化合物的logPow与文献报道值较好的符合,证明该方法可靠。获得了能代表组分疏水化学特征的中药指纹图谱,测得女贞子的主要有效成分齐墩果酸的logPow为3.63。该指纹图谱较为可靠地提供了女贞子中各种成分的logPow,直观地反映出各组分油水分配性质的分布,对中药有效成分提取溶剂的选择、剂型的设计及制剂工艺的改进具有指导意义。

微乳毛细管电色谱电动进样-场放大堆积法检测化妆品中糖皮质激素

采用反向微乳毛细管电色谱电动进样联用场放大堆积，建立了在线富集检测化妆品中6种糖皮质激素分析方法。微乳毛细管电色谱缓冲体系为2．4％（w／w）十二烷基硫酸钠，6．6％（w／w）正丁醇，0．6％（w／w）正辛烷，20mmol／L磷酸盐缓冲液（pH2．2），分离电压-20kV，进样-20kVx54s，进水15kPax40S，检测波长240nm。讨论了样品基质、进样时间和电压、水柱长度对富集效果的影响。在优化条件下，6种激素的富集倍数分别为100～186倍，在0．05～15．0mg／L范围内呈线性关系，相关系数0．9986～0．9997。检出限为20—60μg/L（S／N=3），标准加入量为50μg／L时平均回收率85．9％-103．8％，相对标准偏差均小于5．8％。迁移时间和峰高的日内精密度分别为2．2％和7．9％，13间精密度分别为2．9％和9．0％。

反向微乳毛细管电泳法在线富集技术灵敏检测化妆品中的多环芳烃

要建立了反向微乳毛细管电泳（MEEKC）在线富集技术灵敏检测多环芳烃的方法。采用大体积进样-pH动态连接-扫集微乳毛细管电泳法（LVSS-DypH-MEEKC）对于常规条件下很难分离的6种强亲脂性的多环芳烃中性分子进行富集分离。结果表明,在反相电压下,当微乳液的组成为：2.4%（w/w）SDS、0.6%（w/w）正辛烷、6.6%（w/w）正丁醇、20 mmol/L Na H2PO4缓冲液（pH 2.2）;进HCB时间为20 s（16 kPa）,进样时间为80 s（16 kPa）时,富集效果良好,富集倍数在25～80倍之间,在27 min内实现了对多环芳烃化合物的灵敏检测。将本方法用于化妆品中多环芳烃的检测,回收率在90.6%～95.9%之间,相对标准偏差均小于5.1%（n=5）。

微乳电动毛细管色谱分离山酮类化合物的影响因素

在优化微乳系统(如pH、缓冲液浓度、表面活性剂、助乳剂、油相及添加剂)的基础上,对影响微乳电动毛细管色谱(MEEKC)分离山酮类化合物的因素进行了系统研究。以正辛醇 水分配系数(疏水常数logP)、色谱峰对称因子和理论塔板数作为参数,研究了分离条件的改变对MEEKC分离性能的影响。结果表明,色谱条件的改变对疏水性山酮和亲水性山酮分离选择性的影响存在着显著差异,当微乳体系为50mmol/L硼酸缓冲液(pH9 5)、10%(体积分数)正丁醇、80mmol/L正庚烷、120mmol/L十二烷基硫酸钠和5mmol/L磺酸化β 环糊精,分离电压为20kV和柱温为35℃时,10个山酮中有9个可被基线分离。

微乳液毛细管电动色谱-场放大富集法灵敏分析尿液中的9种麻醉剂类药物

建立了一种微乳液毛细管电动色谱(MEEKC)-场放大富集(FASI)分析尿液中多种麻醉剂(吗啡、可待因、纳洛酮、海洛因、蒂巴因、可卡因、哌替啶、芬太尼、美沙酮)的方法。考察了微乳液组成、分离电压等因素的影响,得到的最佳微乳液组成(质量分数)为0.6%十二烷基硫酸钠、1.2%正丁醇、0.6%乙酸乙酯和97.6%10mmol/L硼砂缓冲液(pH9.5);分离电压为25kV。在上述微乳体系中,9种化合物在15min内得到了基线分离。采用场放大在线富集技术提高了分析灵敏度,检出限(S/N=3)低至0.3μg/L。模拟尿样样品中9种麻醉剂的加标回收率介于79.4%～119.9%之间,日内相对标准偏差小于5.5%。将该方法应用于美沙酮大鼠体外代谢样品的测定,结果令人满意。

毛细管微乳液电动色谱的原理及应用

综述了近年来毛细管微乳液电动色谱(MEEKC)的研究进展。对MEEKC的分离原理进行了阐述;对微乳液的组成和其他影响MEEKC分离的因素进行了总结;对MEEKC在各个领域的应用作以分类评述;并将MEEKC和胶束电动毛细管色谱(MEKC)予以比较。

微乳电动毛细管色谱法分离检测酱油中的氯丙醇

建立了微乳电动毛细管色谱分离3种氯丙醇的方法。以十二烷基硫酸钠(SDS)作为表面活性剂,系统考察了pH值、缓冲溶液类型和浓度、SDS浓度、助表面活性剂浓度、油相浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD),1,3-二氯-2-丙醇(1,3-DCP),2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳微乳缓冲液为1%(V/V)正庚烷,100 mmol/L SDS,10%(V/V)正丁醇和8 mmol/L磷酸二氢钠-硼砂溶液(pH 8.50),检测波长为192 nm,温度20℃,分离电压为15 kV。3种氯丙醇的线性范围为2.0×10-6～3.2×10-5 mol/L,相关系数大于0.996,检出限(S/N=3)为0.95～1.9μmol/L。酱油样品经乙醚液液萃取,萃取平均回收率为93.2%～103.0%,相对标准偏差小于6.5%。本方法应用于实际样品和加标后样品中三氯丙醇的检测,结果满意。

大体积进样-非匀强电场扫集微乳毛细管电动色谱法测定化妆品中糖皮质激素

建立了一个简单有效的微乳毛细管电动色谱（MEEKC）在线富集-大体积进样（LVSI）与非匀强电场扫集（REFS）联用测定化妆品中4种糖皮质激素（泼尼松、氢化可的松、泼尼松龙和倍他米松）的方法。MEEKC的缓冲体系组成为：2.4%SDS,0.6%正辛烷,6.6%正丁醇,30 mmol/L硼酸盐缓冲液（pH 8.2）,分离电压为9.6 kV,进样压力为12.3 kPa,进样时间为95 s,检测波长为230 nm。在最优实验条件下,4种糖皮质激素的富集倍数为853~933倍,在0.015~14 mg/L范围内呈线性关系,检出限（S/N=3）为4~8μg/L。应用此方法分析了化妆品样品,回收率为93.7%~103.8%,相对标准偏差（n=5）均不大于4.4%。

微乳液组成对毛细管微乳液电动色谱的影响

研究了一组电中性芳香族化合物的毛细管微乳液电动色谱分离，考察分离介质微乳液的组成对电动色谱保留时间的影响．实验结果表明，各芳香化合物的保留时间均随表面活性剂浓度增加而增长；内相和助表面活性剂对有、无亲水基团芳香化合物的保留时间有不同的影响规律．选用微乳液组成为８０ｍｍｏｌ／Ｌ正庚烷－１２０ｍｍｏｌ／ＬＳＤＳ－９００ｍｍｏｌ／Ｌ正丁醇－１０ｍｍｏｌ／Ｌ硼砂，样品在１４ｍｉｎ内达到完全分离，理论板数为３×１０５～９×１０５／ｍ．

微乳液毛细管电动色谱应用进展

微乳液毛细管电动色谱(MEEKC)是在胶束电动色谱基础上发展起来的一种电动色谱新技术。近几年来,MEEKC在各个领域的应用又有了长足的进步,尤其是在维生素、药物、天然产物、手性分离、生物分子、环境分析,以及药物疏水性评价上呈现出强势的发展,本文针对这些领域的MEEKC方法进行了评述。

微乳液毛细管电动色谱

从微乳液的组成、性质及其在高效毛细管电泳中的应用等几个方面论述了近 8年来微乳液毛细管电动色谱的发展。