Analysis of serotonin in brain microdialysates using capillary electrophoresis and native laser-induced fluorescence detection

Serotonin or 5-hydroxytryptamine (5-HT) is a major neurotransmitter in the central nervous system. In this work, a method for analyzing 5-HT in brain microdialysis samples using a commercially available capillary electrophoresis (CE) system has been developed. A pH-mediated in-capillary preconcentration of samples was performed, and after separation by capillary zone electrophoresis, native fluorescence of 5-HT was detected by a 266 nm solid-state laser. The separation conditions for the analysis of 5-HT in standard solutions and microdialysates have been optimized, and this method has been validated on both pharmacological and analytical bases. Separation of 5-HT was performed using a 80 mmol/L citrate buffer, pH 2.5, containing 20 mmol/L hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and +30 kV voltage. The detection limit was 2.5 x 10(-10) mol/L. This method allows the in vivo brain monitoring of 5-HT using a simple, accurate CE measurement in underivatized microdialysis samples.     

高效毛细管电泳电导法拆分苯丙氨酸对映体

以未涂层融硅石英毛细管(50 cm×75μm)为分离柱,2 mmol/L NaAc 2 mmol/L HAc 0.5 mmol/LCu2 (pH 4.0)作为电泳运行液,分离电压15 kV,建立了苯丙氨酸对映体的高效毛细管电泳-电导分离检测的方法。对缓冲溶液的种类、浓度、分离电压、有机改性剂等因素对分离的影响进行了讨论,并对拆分机理进行了初步探讨。     

Enantiomer Separation of the Four Stereoisomers of 1-(4-Hydroxy-3-Methoxy)-Phenyl-2-[4-(1,2,3-Trihydroxy-Propyl)-2-Methoxy]-Phenoxy-1,3-Propandiol from Hydnocarpus annamensis by Capillary Zone Electrophoresis with HP-β-CD as Chiral Selector

A capillary zone electrophoresis method with HP-β-CD as chiral selector was established for the chiral separation of four stereoisomers of 1-(4-hydroxy-3-methoxy)-phenyl-2-[4-(1,2,3-trihydroxy-propyl)-2-methoxy]-phenoxy-1,3-propandiol for the first time, which were isolated from Hydnocarpus annamensis. The effects of chiral selector type and concentration, buffer composition, pH and concentration, and cartridge temperature on the enantioseparation were investigated. A baseline separation of the four stereoisomers was achieved in less than 18 min under the optimized conditions: 40 mmol L⁻¹ Borax–NaOH buffer (pH 10.02) in the presence of 100 mmol L⁻¹ HP-β-CD at 15°C and 30 kV. The experimental results showed that the method by capillary zone electrophoresis for the separation of four stereoisomers is powerful, sensitive and fast, requires less amounts of reagents, and can be employed as a reliable alternative to other methods.     

肝糖选择剂-毛细管电泳手性拆分盐酸度洛西汀对映体及分离机制

以肝糖为毛细管电泳手性选择剂,对盐酸度洛西汀对映体的分离进行研究,建立了拆分方法.考察了手性选择剂浓度、运行缓冲液的离子强度、pH值及分离电压对手性分离的影响.在3.0% (m/V)肝糖、50 mmol/L Tris-H3PO4(pH 3.0)的运行缓冲液中,分离电压25 kV时,盐酸度洛西汀两对映体分离度达1.84.对分离机制进行了初步探讨.     

生物组织中丝氨酸对映体的毛细管电泳-非接触式电导分离检测

采用高效毛细管电泳-非接触电导检测法, 使用未涂层石英毛细管(50 μm i.d.×45 cm, L_eff=40 cm), 以3.2 mmol/L氢氧化钠+0.4 mmol/L柠檬酸+2.5 mmol/L乙酸铜+5.0 mmol/L L-精氨酸+15.0 mg/L 羟丙基甲基纤维素为电泳运行液, 实现了未衍生化的D,L-丝氨酸对映体的基线分离和检测. 其线性范围为0.35~30 mg/L, 检出限(S/N=3)为0.10 mg/L. 对影响分离度的因素如手性选择剂、 电泳运行液的组成和浓度、 分离电压和进样方式等进行了探讨. 结果表明, 该方法无需衍生化预处理, 高效低耗, 可实现常见氨基酸共存组分的不干扰测定, 能有效测定小鼠脑组织样品中的D-丝氨酸含量.     

高效液相色谱手性流动相添加法拆分奥昔布宁对映体

采用C18固定相,以羟丙基-β-环糊精为手性流动相添加剂,建立了奥昔布宁对映体的高效液相色谱拆分方法。考察了手性添加剂、有机极性调节剂、缓冲盐的种类和浓度以及流动相的pH值和流速及柱温等因素对对映体分离的影响。在最佳分离条件下,奥昔布宁对映体的分离度为1.54,检测限为1.0 ng。该方法简便,重复性好,比手性固定相法更加经济。     

Chiral separation of ephedrine isomers by capillary electrophoresis using bovine serum albumin as a buffer additive

A method utilizing bovine serum albumin (BSA) as buffer additive for chiral separation by means of capillary electrophoresis is described. Parameters that affect chiral separation, such as buffer pH, buffer concentration, BSA concentration, and organic modifier, are investigated. Baseline resolution of ephedrine-pseudoephedrine and norephedrine-norpseudoephedrine isomers are achieved in an uncoated capillary with a 20 mmol/L phosphate buffer at pH 9.0 in the presence of 10 micromol/L BSA and 15% (v/v) 2-propanol at 25 degrees C. The developed method can be applied for the analysis of ephedra plant extracts that contain the four test drugs.     

毛细管电泳手性选择剂去硫酸基硫酸软骨素C的研究开发及新药西尼地平对映体的拆分

研究开发了一种新型的毛细管电泳多糖手性选择剂去硫酸基硫酸软骨素C,并用于二氢吡啶类药物对映体的分离。建立了新药西尼地平对映体的拆分方法,同时考察了背景电解质pH值、手性添加剂浓度、工作电压等因素对手性分离的影响。优化的背景电解质pH值 为2.50、手性添加剂的质量浓度为30 g/L,工作电压为10 kV。以去硫酸基硫酸软骨素C为毛细管电泳手性选择剂拆分新药西尼地平对映体,操作简单方便,西尼地平两对映体得到了基线分离,分离度达2.01。     

Determination of vitamin C and preservatives in beverages by conventional capillary electrophoresis and microchip electrophoresis with capacitively coupled contactless conductivity detection

The separation and detection of commonly used preservatives (benzoate, sorbate) and vitamin C by both conventional CE and microchip electrophoresis with capacitively coupled contactless conductivity detection is presented. The separation was optimized by adjusting the pH-value of the buffer and the use of hydroxypropyl-beta-CD (HP-beta-CD) and CTAB as additives. For conventional CE, optimal separation conditions were achieved in a histidine/tartrate buffer at pH 6.5, containing 0.025% HP-beta-CD and 0.1 mM CTAB. LOD ranged from 0.5 to 3 mg/L (S/N = 3) and the RSDs for migration time and peak area were less than 0.1 and 2%, respectively. A considerable reduction of analysis time can be accomplished by using microchip electrophoresis without significant loss in sensitivity under optimal separation conditions. A histidine/tartrate buffer at pH 6.5, incorporating 0.06% HP-beta-CD and 0.25 mM CTAB, gave detection limits ranging between 3 and 10 mg/L and satisfactory reproducibilities of < or =0.4% for the migration time and < or =3.5% for the peak area. The methods developed are useful for the quantitative determination of food additives in real samples such as soft drinks and vitamin C tablets.     

新型三唑类抗真菌活性化合物毛细管电泳手性拆分及手性识别机理分子模拟研究

研究了7种新型三唑类抗真菌活性化合物的毛细管电泳法手性分离,利用计算机辅助分子模拟技术研究拆分机理。考察了8种中性环糊精手性添加剂,只有2,6-二甲基-β-环糊精对7种活性化合物都有手性识别能力。在30mmol/L NaH2PO4缓冲液中含2,6-二甲基-β-环糊精30mmol/L,用H3PO4调至pH 2.2,温度20℃,电压20kV,在此条件下7种活性化合物都能达到手性分离,其中4种活性化合物能达到基线分离(Rs>1.5)。应用计算机辅助分子模拟软件Discovery Studio 2.5/Sybyl/Gold模拟2,6-二甲基-β-环糊精与7种活性化合物主客体包结过程,并计算相互结合能,探讨手性识别机理,发现拆分结果与结合能的差异有关,结合能差异越大拆分结果越好。     

3-苯基乳酸的手性毛细管电泳拆分

考察了环糊精种类、环糊精浓度、缓冲溶液pH、分离电压、温度等因素对3-苯基乳酸手性分离的影响,并对分离条件进行了优化。结果表明,采用区带毛细管电泳技术,以0.03 mol/L的羟丙基-β-环糊精为手性选择剂,0.1 mol/L的磷酸缓冲溶液(pH 5.5)为电泳缓冲溶液,26 kV的分离电压,在25 ℃下可使3-苯基乳酸对映体达到基线分离,分离度为1.51。     

Enantioseparation of cetirizine by sulfated-beta-cyclodextrin-mediated capillary electrophoresis

A sulfated beta-cyclodextrin (sulfated beta-CD)-mediated capillary electrophoresis method is described for the enantioseparation of cetirizine using achiral cefazolin as an internal standard. The enantioseparation of the drug was performed in a borate buffer (5 mM, pH 8.7) with 1% sulfated beta-CD (w/v) as chiral selector at 10 kV. Several parameters affecting the separation were studied, including the pH and the concentration of borate buffer and chiral selector. Under optimized conditions, a baseline separation of two enantiomers was achieved in less than 7 min. Using cefazolin as an internal standard (IS), the linear range of the method for the determination of levocetirizine was over 1.0 to 50.0 microg/mL; the detection limit (signal-to-noise ratio = 3) of levocetirizine was 0.5 microg/mL. The method allowed the enantioseparation of cetirizine in bulk samples and enantiomeric purity evaluation of levocetirizine (R-enantiomer) in pharmaceutical tablets (Xyzal), and it was also found to be suitable for enantioseparation in human plasma.     

高效毛细管电泳法检测牛奶中的青霉素中间体以及3种青霉素类药物

建立了高效毛细管电泳(HPCE)同时检测牛奶中青霉素类抗生素中间体6-氨基青霉烷酸(6-APA)以及3种青霉素类药物青霉素钾(PEN)、氨苄青霉素(AMP)和阿莫西林(AMO)的方法。利用正交实验设计,对HPCE中的缓冲液离子浓度和pH值、分离电压、分离温度等分离条件进行了优化。结果表明: 在采用40 mmol/L磷酸二氢钾-20 mmol/L硼砂缓冲体系(pH 7.8)、分离电压为28 kV、分离温度为30 ℃的电泳条件下,4.5 min内可以实现上述4种青霉素类药物的快速分离检测。各组分在1.56～100 mg/L范围内有良好的线性,相关系数(r2)为0.9979～0.9998,加标回收率为84.91%～96.72%,相对标准偏差(RSDs)为1.11%～9.11% (n=6)。该方法简便、快速,可以应用于市售牛奶中4种青霉素类药物的快速检测。     

芳基甘氨酰胺的手性毛细管电泳拆分

 研究了 9种自行合成的芳基甘氨酰胺的手性拆分。以高硫酸化 β 环糊精为手性选择剂 ,在中性而不是常用的强酸性条件下 ,于 6min内基线拆分了全部芳基甘氨酰胺。考察了高硫酸化 β 环糊精浓度、缓冲液类型及浓度、有机添加剂及其含量等对拆分的影响 ,得到优选拆分体系组成为 :1 5g/L高硫酸化 β 环糊精 ,0或 1 0 % (体积分数 )甲醇 ,2 0mmol/L 3 (N 吗啡啉 )丙磺酸 ,pH 6 5。 9种芳基甘氨酰胺的 D 构型均先于 L 构型出峰 ,初步讨论了芳基甘氨酰胺结构与出峰顺序的关系。     

芯片毛细管电泳激光诱导荧光快速分离检测麻黄碱类兴奋剂

研究用芯片毛细管电泳激光诱导荧光检测系统分离测定经7-chloro-4-n itrobenzo-2-oax-1,3-d iazole(NBD-C l)衍生的麻黄碱和伪麻黄碱的实验条件。采用胶束毛细管电动色谱分离体系(12 mmol/L SDS 10mmol/L硼砂缓冲液,pH 9.0),在45 mm长的通道上实现了麻黄碱和伪麻黄碱的快速分离,一次分离小于1.5m in。10~100 mg/L范围内,峰高与浓度呈良好的线性关系,麻黄碱、伪麻黄碱的检出限分别是0.83 mg/L和1.10 mg/L。所建立的方法应用于尿中麻黄碱和伪麻黄碱的分离测定,取得满意的结果。     

MECC分离并测定高粱及玉米中7种农药类环境激素

用毛细管胶束电动色谱成功分离并测定了高粱和玉米中7种农药类环境激素(多菌灵、西玛津、莠去津、毒死蜱、溴氰菊酯、乙草胺和氯氰菊酯)的残留量。研究了电泳缓冲液及表面活性剂等因素的影响,在最佳分离条件(pH 9.0、20 mmol/L磷酸氢二钠+50 mmol/L SDS+5%乙腈为缓冲溶液,分离电压20 kV,检测波长222 nm,实验温度25℃,压力法进样,30 mbar×10 s)下,7种农药在28 min内得到基线分离,质量浓度与其峰面积在5.0～150μg.L-1范围内呈良好线性,检出限为0.6～3.0μg/L,回收率为97%～108%,相对标准偏差为2.2%～4.7%。该方法具有操作简单、快速方便及自动化程度高、重现性好等优点。     

毛细管电泳/非接触式电导法分离检测手性药物氨氯地平对映体

采用毛细管电泳/电容耦合非接触式电导( CE/C4 D),以18 mmol/L柠檬酸+6 mmol/L氨水+12 mg/L羟丙基甲基纤维素(HPMC)+ 35 mmol/L羟丙基-β-环糊精(HP-β-CD)为电泳运行液,熔融石英毛细管(50μm i.d.×45 cm,leff=40 cm),正高压(+15 kV)分离...     

毛细管电泳电致化学发光检测血浆中布比卡因

布比卡因是一种外科局部麻醉剂,使用过量会导致中枢神经系统和心脏血管系统中毒^[1],可引起心脏停博.高效液相色谱和毛细管电泳(CE)^[2]是该药常用的检测方法.     

胶束电动毛细管色谱法检测红曲米中的莫纳可林K

建立了测定红曲米中莫纳可林K含量的胶束电动毛细管色谱(MEKC)方法。考察了运行缓冲液的种类、pH及其浓度、有机添加剂、十二烷基硫酸钠(SDS)的浓度和分离电压等实验条件对电泳分离效果及检测灵敏度的影响。在优化的实验条件下,以20 mmol/L硼砂(pH 10.6,含10%(体积分数)乙醇和40 mmol/L SDS)作为缓冲溶液,莫纳可林K能在23 min内实现很好的基线分离,线性范围为5.00～100.00 mg/L,线性相关系数为0.9976,检出限(以信噪比(S/N)为3计)为0.13 mg/L,加标回收率为98.5%～99.5%。精密度和稳定性试验中,峰面积和迁移时间的相对标准偏差均小于3%,表明重复性良好。该方法简便、快速、灵敏,可用于红曲米中莫纳可林K含量的测定。     

粒子群算法优化中药化学成分的毛细管电泳分离条件

建立了一种基于粒子群优化算法的毛细管电泳条件辅助优化方法。以丹参为研究对象,将改良的色谱指数方程用于评价酚酸类成分的电泳分离性能,用粒子群优化算法对分离条件进行全局寻优,获得最佳的区带电泳分离条件(5.0 mmol/L硼砂,18.5 mmol/L磷酸二氢钠,6.1%乙腈,运行电压18.2 kV)。为进一步改善分离,在所获优化条件下添加50.0 mmol/L SDS,在胶束电动毛细管色谱分离模式下使酚酸类成分(原儿茶醛、丹参素、丹酚酸B等)得到更好分离。本方法准确可靠,可推广应用于其他复杂化学体系的毛细管电泳分离条件优化。