红霉素作为毛细管区带电泳手性选择剂拆分两种联苯双酯类药物

首次使用大环内酯类抗生素红霉素作为毛细管电泳手性选择剂,采用未涂层石英毛细管分离了两种联苯双酯类保肝药物。实验考察了背景电解质中磷酸盐缓冲液的pH值及浓度、分离电压及温度、红霉素浓度、有机添加剂甲醇含量对手性分离的影响。实验结果表明,磷酸盐浓度为50 mmol/L(pH 5.0)、分离电压为-20 kV、红霉素浓度为30 mmol/L、甲醇的体积分数为50%是最佳分离条件。同时证明红霉素可以作为手性选择剂用于毛细管电泳手性分离中。     

不同缓冲体系对毛细管电泳法分离15种核苷类化合物效果的比较

对毛细管电泳法分离15种核苷类化合物所用的不同缓冲液体系进行了系统比较,确定不同模式毛细管电泳法分析多种核苷类化合物的最适合背景缓冲液体系(BGE)。分别以四硼酸钠、磷酸氢二钠、乙酸钠、碳酸氢钠、乙酸铵和乙二胺(DEA)为背景电解质,对毛细管区带电泳(CZE)、毛细管电泳-电喷雾飞行时间质谱(CE-ESI-TOF/MS)以及胶束电动毛细管电泳(MEKC)3种模式进行比较,并对其中几种优势缓冲体系进行了优化。结果表明,CZE模式下使用四硼酸钠和磷酸氢二钠缓冲体系无法同时分离15种核苷类化合物,因此只适用于分析核苷类化合物数量较少的样品。而使用含有2%丙酮的300 mmol/L DEA能完全分开15种核苷类化合物,且分辨率和峰形良好。MEKC模式下,以25 mmol/L磷酸氢二钠(添加70 mmol/L十二烷基磺酸钠(SDS))为缓冲盐的分离结果最佳,并且此方法能成功应用于海洋生物海葵中核苷类化合物的分离。CE-ESI-TOF/MS分析中,以20 mmol/L乙酸铵(pH 10.0)为背景电解质,正离子模式检测,15种核苷类化合物的质谱信号均良好,检测灵敏度明显优于文献中报道的使用DEA缓冲体系的结果。本研究阐明了不同缓冲体系对15种核苷类化合物分离的适用性,为毛细管电泳技术在复杂基质中多种核苷类化合物的分离方法中的应用奠定了基础。     

可视移动中和反应界面离线富集-毛细管电泳法检测电镀废水中痕量重金属离子

建立了一种可视化的、利用移动中和界面离线富集-毛细管电泳检测电镀水中痕量重金属离子的新方法。在该富集系统中,阳极电解液为2.1 mmol/L HCl-98 mmol/L KCl-痕量重金属离子,阴极电解液为4.0 mmol/L NaOH-96 mmol/L KCl,界面向阴极移动,分离电压为180 V,阴极电解液和阳极电解液的流速均为1 mL/min。富集后凝胶中的金属离子浓度用毛细管电泳检测,标准曲线在实验浓度范围内均有良好的线性关系(r≥0.9985),预富集倍数达80～150倍,Cu(II)、Zn(II)、Ni(II)、Mg(II)、Ca(II)、Cr(III)和Fe(III)的检出限分别为0.163、0.256、0.077、0.153、0.203、0.062和0.142 mg/L,均明显低于国家规定标准;日内和日间精密度均小于7.42%。所建方法已成功用于实际电镀废水样品中痕量重金属离子的富集和检测。     

西他沙星差向异构体的毛细管电泳分离

以γ-环糊精和D-苯丙氨酸为手性选择剂,采用毛细管区带电泳成功地分离了新型抗菌素西他沙星差向异构体。考察了添加剂的种类、浓度和缓冲溶液的pH对毛细管电泳分离西他沙星的影响。分离电压为15 kV,选用60 cm(有效长度52.5 cm)×50 μm i.d.的石英毛细管,缓冲溶液组成为10 mmol/L KH2PO4-K2HPO4(pH 4.5),10 mmol/L CuSO4,20 mmol/L γ-环糊精和 10 mmol/L D-苯丙氨酸。实验结果表明,添加剂的种类和浓度是影响西他沙星手性分离的重要因素,只有当 D-苯丙氨酸、铜离子和γ-环糊精同时存在并达到一定浓度时,西他沙星差向异构体在毛细管电泳中才具有良好的分离效果。该方法可用于西他沙星差向异构体的定量分析。     

配体交换毛细管区带电泳拆分未衍生化氨基酸

以铜(Ⅱ)-L-谷氨酸络合物为手性分离选择剂,对苯丙氨酸、酪氨酸和色氨酸3种非衍生芳香族氨基酸的手性对映体拆分进行了研究,建立了一种快速、简便拆分未衍生化的氨基酸对映体的配体交换毛细管电泳方法.在使用10 mmol/L NH4AC(pH 5.0),5 mmol/L CuSO4和10 mmol/L L-谷氨酸的条件下,成功地拆分了苯丙氨酸、酪氨酸手性对映体;色氨酸手性对映体也得到部分分离;考察了电泳缓冲液组成、pH值等影响分离效果的因素.     

毛细管电泳法同时测定化妆品中氢醌、苯酚和防腐剂

采用毛细管电泳法对化妆品中氢醌、苯酚、山梨酸和苯甲酸进行了分离研究,考察了缓冲溶液的种类和pH值对分离的影响.以15 mmol/L硼砂(pH 9.2)为电泳缓冲液,采用压力进样方式,在20 kV恒压下进行分离,并在波长240 nm处检测,各组分可达到基线分离.4种标样在0.5～ 100.0 mg/L范围内呈良好线性关系...     

毛细管电泳电化学法分离检测盐酸克伦特罗、特布他林和沙丁胺醇

建立了毛细管电泳电化学法对盐酸克伦特罗、特布他林和沙丁胺醇进行分离检测。方法采用胶束电泳体系,以铂圆盘为工作电极,考察了检测电位、缓冲液浓度和pH、十二烷基硫酸钠(SDS)浓度、分离电压等因素的影响。3个分离物在10 kV的分离电压、缓冲体系为15 mmol/L(pH 9.0)硼砂+20 mmol/L SDS条件下得到分离。盐酸克伦特罗、特布他林和沙丁胺醇的线性范围分别为2.0～400,3.5～700,5.0～1000μg/L。方法已用于猪肉样品的检测。     

应用四甲基氢氧化铵控制电渗流的毛细管电泳方法分离多沙唑嗪及其中间体的对映体

建立了毛细管电泳手性分离多沙唑嗪中间体对映体的方法,并同时分离了多沙唑嗪对映体。考察了不同种类季铵盐对电渗流及分离的影响,其中四甲基氢氧化铵(TMB)能有效控制电渗流并提高组分的分离度。实验还考察了其他因素,如pH值、分离电压和磷酸二氢钠浓度对分离的影响。所用的毛细管为40 cm(有效长度30 cm)×50 μm,缓冲液为12 mmol/L β-环糊精、30 mmol/L TMB、60 mmol/L 磷酸二氢钠(pH 2.2),分离电压为20 kV。在此条件下多沙唑嗪及其中间体的对映体均达到了基线分离。实验结果表明,一些用β-环糊精不能完全分离的对映体通过加入TMB控制电渗流能达到满意的分离效果。     

竹荪加工中废弃物多糖水解液的胶束毛细管电泳研究

本文建立了胶束毛细管电泳测定竹荪加工废弃物的多糖组成的新方法。考察了缓冲溶液、表面活性剂、运行电压、温度等因素对分离效果的影响。选择25mmol/L硼酸盐(pH=9.4)-20mmol/L十二烷基磺酸钠(SDS)为电泳介质,分离电压为15kV,分离温度为25℃,9min中内可实现对竹荪加工中废弃物中多糖的单糖组分的分离检测。     

毛细管电泳-间接紫外法检测蜂蜜中的多种金属离子

探讨了一种利用毛细管电泳测定K+、Ba2+、Ca2+、Na+、Mg2+、Fe2+、Zn2+、Cd2+、Li+和Cu2+10种金属离子的方法。考察了紫外生色剂的浓度和pH值对分离效果的影响,并优化了分离条件。结果表明,咪唑浓度为15 mmol/L(pH 3.7),分离电压为20kV时,10种金属离子可在7min内实现基线分离。10种金属离子的线性范围为0.06～60.0mg/L,相关系数为0.9995～0.9999,检出限为0.01～0.21mg/L。标准样品的回收率为95%～104%,5次测定的相对标准偏差为0.9%～5.8%。将该法用于6个蜂蜜样品的测定,结果满意。     

Determination of enrofloxacin and its metabolite ciprofloxacin by high performance capillary electrophoresis with end-column amperometric detection

Enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP) were determined by capillary zone electrophoresis (CZE) with end-column amperometric detection. The effect of several factors, such as pH and concentration of running buffer solution, separation voltage, injection time, and working potential, on CZE were investigated to establish the optimal conditions of separation and detection. Under a given set of conditions (pH 8.00 phosphate buffer solution (20 mmol/L); +0.95 V for the working potential; 18 kV for the separation voltage; sample injection at 18 kV for 10 s), the compounds investigated can be well separated and detected within 8 min. Excellent linearity was observed between peak currents and concentration of analytes in the range from 0.034 to 70.0 mg/kg for these two compounds. The detection limits (S/N= 3) for enrofloxacin and ciprofloxacin were 13.68 mg/kg and 14.35 mg/kg, respectively, which were about 7-fold lower than the maximum residue limits (MRLs) established by the European Union. A simple sample pretreatment method was developed and proved to be effective in obtaining good recoveries and short analysis time. The developed CE-AD method was simpler, faster, and less cost intensive than other reported methods, and allows the determination of ENR and its metabolite CIP in contaminated eel liver samples and other animal tissue samples at the required maximum residue limits.     

Development of a solid-phase microextraction method with micellar desorption for the determination of chlorophenols in water samples. Comparison with conventional solid-phase microextraction method

A novel analytical method is presented for the determination of chlorophenols in water. This method involves pre-concentration by solid-phase microextraction (SPME) and an external desorption using a micellar medium as desorbing agent. Final analysis of the selected chlorophenols compounds was carried out by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Optimum conditions for desorption, using the non-ionic surfactant polyoxyethylene 10 lauryl ether (POLE), such as surfactant concentration and time were studied. A satisfactory reproducibility for the extraction of target compounds, between 6 and 15%, was obtained, and detection limits were in the range of 1.1-5.9ngmL(-1). The developed method is evaluated and compared with the conventional one using organic solvent as a desorbing agent. The method was successfully applied to the determination of chlorophenols in water samples from different origin. This study has demonstrated that solid-phase microextraction with micellar desorption (SPME-MD) can be used as an alternative to conventional SPME method for the extraction of chlorophenols in water samples.     

Determination of steroid sex hormones in urine matrix by stir bar sorptive extraction based on monolithic material and liquid chromatography with diode array detection

A simple, rapid and sensitive method for simultaneous determination of six steroid sex hormones in urine matrix was developed by the combination of stir bar sorptive extraction (SBSE) with high performance liquid chromatography (HPLC) and diode array detection (DAD). A poly (methacrylic acid stearyl ester-ethylene dimethacrylate) was synthesized and selected as SBSE extraction medium. To achieve the optimum extraction performance, several parameters, including agitation speed, desorption solvent, extraction and desorption time, pH value, inorganic salt and organic solvent content of the sample matrix were investigated. Under the optimized experimental conditions, low detection limits (S/N=3) and quantification limits (S/N=10) of the proposed method for the target compounds were achieved within the range of 0.062-0.38 and 0.20-1.20 ng/mL, respectively from spiked urine, respectively. The calibration curves of six steroid sex hormones showed good linearity ranging from 1.0 to 200 ng/mL with linear coefficient R2 values above 0.990. Good method reproducibilities presented as intra- and inter-day precisions were also found with the R.S.D.s less than 9.2 and 10.0%, respectively. Finally, the proposed method was successfully applied to the determination of the target compounds in a urine sample from a pregnant woman.     

New studies of the plasma emission detector

Being an element-selective detector, the plasma emission detector was used to determine carbon in organic compounds. Experiments were carried out with the aid of osculating interference filters and lock-in amplifiers. The obtained signals were processed by a fast-Fourier-transform analyzer to study their frequency spectra. Results are given for the detection of carbon. Furthermore studies on the influence of angle-adjustment, microwave power, photomultiplier voltage and oscillation frequency on the determination of fluorine in organic compounds were carried out and results for detection limits and dynamic range of this method are presented.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Separation and determination of flavonoids in Agrimonia pilosa Ledeb. by capillary electrophoresis with electrochemical detection

Five flavonoids (catechin, hyperoside, quercitrin, quercetin, and rutin) were separated and determined by capillary electrophoresis with electrochemical detection. Effects of several important factors, such as the pH and concentration of running buffer, separation voltage, injection time, and detection potential were investigated to determine the optimum conditions. The five flavonoids were baseline separated within 20 min in a 60 cm length capillary at a separation voltage of 19.5 kV with a running buffer consisting of 60 mmoL/L Na2B4O7 - 120 mmoL/L NaH2PO4 (pH = 8.8). The relationship between peak current and analyte concentration was linear over about two orders of magnitude with detection limits (S/N = 3) ranging from 0.02 to 0.05 microg/mL for all compounds. This method was successfully used to determine the above five flavonoids in Agrimonia pilosa Ledeb. with relatively simple extraction procedures, and the assay results were satisfactory.     

Glass-fiber reinforced poly(acrylate)-based sorptive materials for the enrichment of organic micropollutants from aqueous samples

A novel and simple approach to sorptive materials for the extraction of organic compounds from environmental samples is presented. It entails the use of glass fiber fabric strips coated with a customized poly(acrylate) (PA) formulation as extraction medium. Analytes were enriched by means of shaking of the PA strip in the sample and then subsequently thermally desorbed and analyzed by GC-MS. The performance of the sorptive materials was evaluated by the enrichment of compounds with different polarities (phenols, hexachlorobenzene and hexachlorocyclohexanes) from water samples. Parameters that affect the extraction process such as pH, ionic strength of the solvent, mixing mechanism, extraction time and desorption conditions were investigated. The extraction abilities of the PA extraction medium were compared with that of commercially available poly(dimethylsiloxane) (PDMS) Twisters. The results revealed that the new material shows higher affinity for phenolic compounds presumably due to the presence of polar groups. The partition coefficients for the PA strips estimated in this work were up to 15 times higher than for the PDMS Twister, resulting in higher recoveries and lower detection limits. The method was applied for the quantification of the aforementioned compounds in contaminated surface water samples from Bitterfeld (Germany). Using both PA strips and PDMS Twisters, good agreement of the extraction data was achieved.     

4-(6,7-Dihydro-5,8-dioxothiazolo[4,5-g]phthalazin-2-yl)benzoic acid N-hydroxysuccinimide ester as a highly sensitive chemiluminescence derivatization reagent for amines in liquid chromatography

4-(6,7-Dihydro-5,8-dioxothiazolo[4,5-g]phthalazin-2-yl)benzoic acid N-hydroxysuccinimide ester was synthesized as a highly sensitive and selective chemiluminescence derivatization reagent for primary and secondary amines in liquid chromatography. Methyl-n-octylamine, n-nonylamine and n-decylamine were used as model compounds to optimize the derivatization, separation and chemiluminescence reaction conditions. This reagent reacts selectively with amines in the presence of triethylamine to give the highly chemiluminescent derivatives, which produce chemiluminescence by reaction with hydrogen peroxide in the presence of potassium hexacyanoferrate(III) in an alkaline medium. The chemiluminescent derivatives of the three amines can be separated within 20 min by reversed-phase liquid chromatography with isocratic elution, followed by chemiluminescence detection. The detection limits (signal-to-noise ratio=3) for primary and secondary amines are at sub-fmol levels for a 20-microl injection. Furthermore, this method was applicable to the determination of amantadine in human plasma.     

Separation of caffeine and theophylline in poly(dimethylsiloxane) microchannel electrophoresis with electrochemical detection

A method for the rapid separation and sensitive determination of caffeine and theophylline was presented in poly(dimethylsiloxane) (PDMS) microchannel electrophoresis integrated with electrochemical detection. By using methanol as an additive, the peak shape and resolution were essentially improved. The analytes were well separated within only 40s in the running buffer of 5.0mM borate solution (pH 9.2) containing 10% (v/v) methanol. The linear ranges were from 6microM to 0.6mM and the detection limits were 4microM for caffeine and theophylline, respectively. The proposed method has been successfully applied to determine caffeine and theophylline in rat serum and urine.     

毛细管电泳-激光诱导荧光法测定草甘膦、草胺膦及氨甲基膦酸

建立了一种快速、有效的毛细管电泳分离-激光诱导荧光检测有机磷除草剂草甘膦、草胺膦和草甘膦的代谢物氨甲基膦酸的方法。将荧光衍生试剂5-(4, 6-二氯三嗪基)氨基荧光素(DTAF)成功用于衍生上述3种化合物。最佳衍生条件: DTAF的浓度为1.0 μmol/L,以50 mmol/L硼酸(pH 9.5)作为缓冲溶液,在30 ℃下反应40 min。以pH 9.5的30 mmol/L硼酸缓冲溶液(含15 mmol/L Brij-35)作为电泳背景电解质,3种衍生物得到基线分离。在优化的条件下,草甘膦、草胺膦、氨甲基膦酸的检出限分别为3.21、6.14和1.99 ng/kg。将该方法应用于环境水样和土壤中除草剂及代谢物的测定,回收率为91.3%～106.0%。该方法准确、灵敏,可满足环境样品中有机磷农药及其代谢物残留的检测要求。     

Determination of hydroxy metabolites of polycyclic aromatic hydrocarbons by fully automated solid-phase microextraction derivatization and gas chromatography-mass spectrometry

A fully automated sample pretreatment method was developed for the detection of mono and dihydroxy metabolites of polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry in the selected ion monitoring mode. Direct immersion solid-phase microextraction for the extraction of target compounds and the headspace on-fiber silylation with N,O-bis(trimethylsilyl)trifluoroacetamide were performed automatically by a multipurpose autosampler (MPS2). The operating conditions including extraction time, derivatization time, ionic strength, pH, and incubation temperature were optimized. Calibration responses of nine metabolites of PAHs over a concentration range of 0.1-100 microg L(-1) with a correlation coefficient of 0.999 were obtained. The detection limits of the nine metabolites in mini pore water, minimal salts medium and soil extract culture medium were in the range of 0.001-0.013, 0.002-0.024 and 0.002-0.134 microg L(-1), respectively, while the respective quantification limits were 0.003-0.044, 0.005-0.081 and 0.008-0.447 microg L(-1). The reliability was confirmed by the traditional solid-phase extraction method. The proposed method could be used to analyze the metabolites of PAHs degraded by microorganisms such as algae and to determine the biodegradation pathways of PAHs.