采用隔离池的毛细管电泳-间接紫外吸收法测定茶叶中的氨基酸

改进的毛细管电泳-间接紫外吸收法采用了自制隔离池,以对氨基苯甲酸(PAB)为背景电解质,对茶叶中的氨基酸进行了测定。PAB能够提高分离效率,降低检出限。隔离池的使用避免了PAB的电极反应,降低了基线噪声,维持了两缓冲液池间的电流导通。研究了背景电解质的浓度、pH值以及电渗流改性剂的种类和浓度对氨基酸分离的影响。在优化的实验条件下,16种氨基酸在14 min内达到了基线分离,峰面积的相对标准偏差小于5%(n=5),检出限为1.7~4.5 μmol/L,回收率为83.0%~106%。该法快速、便捷和灵敏,已成功应用于茶叶中11种游离氨基酸的检测。     

毛细管胶束电动色谱法分析PTH氨基酸

建立了用毛细管胶束电动色谱法（MEKC）分离19种PTH氨基酸的方法,并探讨了电压、pH值、温度、胶束浓度对氨基酸迁移时间的影响。方法具有速度快、灵敏度高、样品用量少的优点。     

毛细管区带电泳法测定尿中甲酸含量

采用高效毛细管区带电泳法测定人体尿中甲酸含量,尿样经过滤后直接进样,方法简单、快速,测定结果令人满意。电泳电解质体系采用５ｍｍｏｌ／Ｌ邻苯二甲酸氢钾,０．５ｍｍｏｌ／Ｌ十六烷基三甲基溴化铵,ｐＨ６,５０ｃｍ×５０μｍｉ．ｄ．熔融石英毛细管（有效长度４８．５ｃｍ）,检测波长２１０ｎｍ,负电源,分离电压３０ｋＶ,压力进样,恒温２５℃,每次电泳前用０．１ｍｏｌ／ＬＮａＯＨ及缓冲溶液对毛细管各冲洗５ｍｉｎ。同时,采用检测波长与参比波长对调的方法使负峰转变为正峰。     

High-performance capillary zone electrophoretic assay for markers of diabetic nephropathy in plasma and urine

A new high-performance capillary zone electrophoretic assay for creatine (Cr), creatinine (Cn), urea (U) and uric acid (Ua), markers of human diabetic nephropathy, both in plasma and urine has been developed with UV detection at 200 nm. The plasma sample was deproteinized with trichloroacetic acid and centrifuged at 10 000 rpm for 10 min. The urine sample was diluted 20-fold with buffer before analysis. The optimum separation conditions for the markers was investigated with respect to the concentration of the buffer, the pH, the voltage and the capillary temperature. Baseline separation was achieved in 25 mmol/L phosphate buffer (pH 3.45) using a 21 cm x 75 microm I.D. fused-silica capillary at 40 degrees C with an electric field of 1190 V/cm. The calibration curves showed good linearity in the range 3.5-1000, 0.18-700, 500-5000 and 2-800 microM (r2 min > 0.998) for Cr, Cn, U and Ua, respectively. The proposed method also has a high reproducibility (peak area RSD max < 3%) and has been successfully applied to the determination of clinical samples.     

Attomole catechins determination by capillary liquid chromatography with electrochemical detection.

Attomole quantities of catechins were determined by a capillary liquid chromatography system with electrochemical detection (CLC-ECD) and the system is applied to the determination of catechins in human plasma. The eight catechins: catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (Cg), epicatechin gallate (ECg), gallocatechin gallate (GCg), and epigallocatechin gallate (EGCg), were separated within 10 min using a capillary column (0.2 mm i.d.) and a mobile phase of phosphoric acid (85%)-methanol-water (0.5:27.5:72.5, v/v/v), and were detected at +0.85 V vs. Ag/AgCl. Peak heights were found to be linearly related to the amount of catechins injected, from 200 amol to 500 fmol (r > 0.998). The detection limits of the catechins were 61 amol for EGC, 75 amol for EC, 54 amol for GC, 61 amol for C, 67 amol for GCg, 75 amol for EGCg, 75 amol for ECg and 89 amol for Cg (S/N = 3). Because the present method is highly sensitive and allows facile pretreatment for plasma sample, the time courses of concentrations of catechins (GCg, EC, EGCg, ECg, and Cg) and their conjugates in human plasma obtained from a 10 microl plasma sample after ingestion of green tea could be determined.     

毛细管电泳-激光诱导荧光检测法测定卡托普利和N-乙酰-L-半胱氨酸

建立了一种高效、快速的毛细管电泳分离-激光诱导荧光(CE-LIF)检测卡托普利(CAP)和N-乙酰-L-半胱氨酸(NAC)的分析方法。采用1,3,5,7-四甲基-8-溴甲基-二氟二硼-二吡咯甲川(TMMB-Br)为柱前衍生试剂,在50 mmol/L磷酸盐缓冲溶液(pH=8.5)中,40℃下进行衍生反应10min。以荧光素为内标,25mmol/L硼酸盐缓冲溶液(pH=9.5)为电泳背景电解质,14min内达到基线分离。CAP和NAC的检出限分别为0.65nmol/L、0.76nmol/L。将该方法应用于人体尿液和血清中这两种物质的测定,回收率在97.0%~105.7%之间。     

柱前衍生高效液相色谱法测定茶叶中茶氨酸及γ-氨基丁酸含量

对茶叶中的茶氨酸和γ-氨基丁酸(GABA)建立了柱前衍生方法,并利用高效液相色谱法(HPLC)对衍生物进行了测定。采用邻苯二甲醛(OPA)及N-乙酰-L-半胱氨酸(NAC)为衍生试剂,考察了脯氨酸(Pro)、茶多酚(Tp)及维生素C(Vc)等对衍生体系的影响,并对色谱分离条件进行了优化。结果表明,茶氨酸与GABA衍生物在色谱柱上的保留行为与分离效率主要受流动相pH及缓冲盐浓度的影响;Pro、Tp及Vc对茶氨酸的衍生产率影响较小。而Vc可以提高GABA检测的灵敏度,并能稳定衍生用储备液。GABA与茶氨酸衍生后的方法检出限(LOD)分别为3.01×10~5mmol/L和7.98×10~5mmol/L;定量限(LOQ)分别为9.99×10~5mmol/L和2.658×10~4mmol/L;线性范围分别为0.01～0.4 mmol/L(相关系数为0.996)和0.05～0.8 mmol/L(相关系数为0.995);方法的回收率分别为99.29%～119.60%和93.18%～141.06%(除本身含茶氨酸量高的绿茶中回收率为62.88%外)。这说明经优化的柱前衍生-高效液相色谱体系可用于茶叶中两种特征性氨基酸的测定。     

Micellar electrokinetic chromatography method for the determination of sulfamethoxazole, trimethoprim and their main metabolites in human serum

A complete analytical procedure, including sample clean-up and a micellar electrokinetic chromatographic method, is presented for the determination of sulfamethoxazole, trimethoprim, and their main metabolites by using 20 mmol L(-1) borate buffer (pH 9.3), 25 mmol L(-1) sodium dodecylsulfate, and 5% v/v acetonitrile as electrolyte. The separation was carried out at 30 kV and 20 degrees C in a fused silica capillary (60.2 cm x 75 microm inner diameter) fitted with a window in the capillary cartridge of 100 x 800 microm. The detector response was linear from the limit of quantification to 3 mg L(-1) for the individual components. The limits of quantification ranged from 0.13 up to 0.24 mg L(-1). The method was applied to human serum, previously spiked at different concentrations of all the analytes, and recoveries between 95% and 108% were obtained.     

Dynamic pH junction-sweeping for on-line focusing of dipeptides in capillary electrophoresis with laser-induced fluorescence detection

In this paper, we developed a simple and effective on-line focusing technique combining dynamic pH junction and sweeping by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. Dynamic pH junction-sweeping is defined when the sample has a different buffer pH (dynamic pH junction condition) and is devoid of micelles (sweeping condition) relative to the background electrolyte (BGE). This hyphenated focusing mode was applied to the sensitive and selective focusing of four dipeptides: Tyr-Phe, Tyr-Leu, Trp-Gly, and Ala-Gln. Picomolar detectability of these dipeptides by CE-LIF detection was demonstrated through effective focusing of large sample volumes (up to 39% capillary length) using the dual pH junction-sweeping focusing mode. 25 mmol L(-1) sodium dihydrogen phosphate, pH 2.5 was used as the sample matrix, and 100 mmol L(-1) borate, 21 mmol L(-1) sodium dodecylsulfate (SDS), 16 mmol L(-1) Brij35, pH 9.0 as the background solution (BGS). The concentration detection limits (S/N = 3) of the four dipeptides were in the range of 1.0-5.0 pmol L(-1). The developed method has been successfully used for the determination of dipeptides in human serum samples.     

咔唑-9-乙基氯甲酸酯柱前衍生氨基酸胶束电动色谱分离

采用一种新型紫外、荧光衍生试剂咔唑-9-乙基氯甲酸酯对9种氨基酸(丝氨酸、苏氨酸、甘氨酸、谷氨酸、天冬氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸)进行柱前衍生,采用胶束电动色谱模式在14 min内完成分离。分离条件：以pH 9.0的 20 mmol/L硼酸盐-30 mmol/L十二烷基硫酸钠(SDS)溶液（含3%(体积分数)乙腈)为缓冲溶液,柱温25 ℃,分离电压18 kV,紫外检测波长214 nm。该方法的线性范围为0.025~0.25 mmol/L,检出限为2.15~2.46 μmol/L。     

毛细管区带电泳法测定血浆中的苯妥英钠

 建立了以毛细管区带电泳测定血浆中苯妥英钠含量的方法。此法具有良好的重现性和线性关系 ,日内、日间的平均相对标准偏差分别为 3.1%和 4 .7% ,平均回收率大于 95 % ,标准曲线的相关系数为 0 9985 ,是一种简便、快速、准确、灵敏的测定方法 。     

Enantiomeric determination of praziquantel and its main metabolite trans-4-hydroxypraziquantel in human plasma by cyclodextrin-modified micellar electrokinetic chromatography

A capillary electrophoresis method for the simultaneous quantitation of praziquantel and its main metabolite trans-4-hydroxypraziquantel enantiomers in human plasma was developed and validated using cyclodextrin-modified micellar electrokinetic chromatography. Sample clean-up involved a single-step liquid-liquid extraction of plasma with toluene after the addition of NaCl. The complete enantioselective analysis was obtained in less than 7 min using 2% w/v sulfated beta-cyclodextrin as chiral selector and 20 mmol/L sodium deoxycholate as surfactant, in 20 mmol/L sodium borate buffer, pH 10. A 50 microm x 42 cm uncoated fused-silica capillary was used for the analysis, performed at a voltage of 18 kV and at 20 degrees C. The calibration curves were linear over the 125-625 ng/mL concentration range. The mean recoveries for praziquantel and trans-4-hydroxypraziquantel were up to 96 and 71%, respectively, with good precision. All four enantiomers were quantified at two concentration levels (200 and 600 ng/mL) with precision and accuracy below 15%. The quantitation limit was 50 ng/mL for (-)-(R)- and (+)-(S)-praziquantel and 62.5 ng/mL for (-)-(R)- and (+)-(S)-trans-4-hydroxypraziquantel, using 1 mL of human plasma.     

Micellar electrokinetic capillary chromatography as an alternative method for the determination of dexamethasone, trimethoprim, and polymyxin B

A micellar electrokinetic capillary chromatographic method is presented which enables quantification of dexamethasone, polymyxin B and trimethoprim in synthetic mixtures and pharmaceutical products. Separation was carried out at 25 degrees C and 30 kV, with 10 mmol L(-1) borate-phosphate buffer adjusted to pH 8 as electrolyte, with 50 mmol L(-1) sodium dodecyl sulfate. Under these conditions separations were performed in 10 min. The limits of detection and quantification were approximately 2 mg L(-1) for each component, except for polymyxin B. The method was applied to different commercial formulations.     

毛细管电泳-间接电化学发光法对茶叶中百草枯农药残留的检测

基于农药百草枯对钌联吡啶-三丙胺(TPA)体系的电化学发光具有显著的抑制作用,建立了毛细管电泳-间接电化学发光检测茶叶中残留农药百草枯的新方法.讨论了初始电位、钌联吡啶和TPA浓度、进样电压、进样时间、运行缓冲溶液的浓度与pH值等条件对百草枯检测灵敏度的影响.确定最佳实验条件为1.20 V初始电压、0.7 mmol/L钌联吡啶、0.6 mmol/L TPA、9 kV进样电压、9 s进样时间、35 mmol/L磷酸盐(pH 8.5)为运行缓冲溶液.在优化实验条件下,百草枯浓度在5×10~(-7) 5×10~(-5)mol/L范围内呈良好线性(相关系数为0.994 5),检出限为9.4×10~(-8) mol/L.对5×10~(-5) mol/L百草枯标准溶液连续测定5次,相对峰高与迁移时间的相对标准偏差分别为3.7%和2.1%.该方法对2.0×10~(-6)、1.0×10~(-5) mol/L百草枯标样的萃取回收率分别为74%和83%,相对标准偏差分别为15%、4.2%(n=5).     

Separation and determination of vanadium in fertiliser by capillary electrophoresis with a light-emitting diode detector

A method has been developed for determination of vanadium, as an anionic ternary complex of vanadium(V) with 4-(2-pyridylazo) resorcinol (PAR) and hydrogen peroxide, after separation by capillary electrophoresis (CE). The optimum conditions for the formation of the ternary complex were acetate buffer (3 mmol L(-1)) at pH 6 containing 0.15 mmol L(-1) PAR and 7.1 mmol L(-1) H(2)O(2). The CE separation was conducted using 15 mmol L(-1) acetate buffer at pH 6 as the background electrolyte; the separation potential was -30 kV and the injection time 100 s. The vanadium complex was detected photometrically at 568 nm, by use of a light-emitting diode (LED); the detection limit was 19 ppb. The method was applied to the analysis of vanadium in fertilisers. Clean-up of the digested fertiliser sample, with Sep-Pak C(18) coated with tetrabutylammonium hydroxide, before analysis was used to remove matrix ions which otherwise caused electrophoretic de-stacking. Vanadium levels found in the fertiliser samples by use of the CE method were found to be comparable with results obtained by HPLC and ICP-MS.     

毛细管区带电泳技术快速分离检测爆炸残留物中的无机离子

利用间接紫外毛细管区带电泳方法完成了对爆炸残留物中7种无机离子(K+,NH+4,NO-2,NO-3,SO2-4,ClO-3,ClO-4)的分离检测。阳离子测定采用的缓冲体系为10 mmol/L吡啶（pH 4.5）-3 mmol/L冠醚,K+和NH+4在2.6 min内达到基线分离,检出限分别为0.25 mg/L和0.10 mg/L(S/N=3)。阴离子测定采用的缓冲体系为40 mmol/L硼酸-1.8 mmol/L重铬酸钾-2 mmol/L硼酸钠（pH 8.6）,氢氧化四甲铵为电渗流改性剂,5种阴离子在4.6 min内达到基线分离,检出限为0.10～1.85 mg/L。该方法已成功地应用于实际爆炸物样品种类的判定分析,取得了很好的结果。     

毛细管电泳-安培检测法用于7-甲基鸟苷与丝裂霉素C分离检测的研究

建立了一种同时分离检测7-甲基鸟苷与丝裂霉素C的毛细管电泳-安培检测方法。在950 mV电极(工作电极:0.3 mm微型石墨圆盘电极;参比电极:Ag/AgCl;辅助电极:Pt丝)电位下,于20 mmol/L的磷酸盐缓冲体系(pH 9.4)中,采用18 kV的分离电压进行分离。在最佳条件下,7-甲基鸟苷与丝裂霉素C在10 min内实现分离,7-甲基鸟苷与丝裂霉素C的线性范围均为0.50~50 mg/L,检测限分别为0.050 mg/L与0.025 mg/L。将该方法用于模拟尿样和模拟兔血清样的检测,7-甲基鸟苷与丝裂霉素C的回收率为93.0%～97.2%,结果令人满意。     

Separation and determination of carnosine-related peptides using capillary electrophoresis with laser-induced fluorescence detection

A capillary electrophoresis (CE) method with laser-induced fluorescence (LIF) detection was developed for the separation and detection of carnosine-related peptides (carnosine, anserine, and homocarnosine). A sensitive and fluorogenic regent, 3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde (CBQCA) was selected as a precapillary labeling reagent for imidazole dipeptides to form isoindole derivatives. The optimized molar ratio between CBQCA and peptide was found to be 75:1, and 50 mmol/L borate buffer (pH 9.2) was used for the derivatization in order to achieve good efficiency. Three imidazole dipeptides were baseline-separated within 20 min by using 112 mmol/L sodium borate (pH 10.4-10.8) as running buffer. Concentration detection limits (signal-to-noise ratios) for carnosine, anserine, and homocarnosine were 4.73, 4.37, and 3.94 nmol/L, respectively. This method has been applied to the analysis of human cerebrospinal fluid (CSF) and meat dry powder of pig and sheep. Recoveries were in the range of 82.9-104.8% for homocarnosine in CSF. For carnosine and anserine, the recoveries are 98.3% and 80.2% in meat dry powder of pig and 111.2% and 112.8% in meat dry powder of sheep, respectively.     

Determination of pyruvic acid by using enzymic fluorescence capillary analysis

A new method (P-LE-FCA) for the determination of pyruvic acid was proposed based on liquid enzyme method (LE) and fluorescence capillary analysis (FCA). The optimum experimental conditions were as follows: the excitation and emission wavelengths were 350 and 460 nm, respectively; the reaction time and temperature were 20 min and 38 degrees C, respectively; the pH of phosphate buffer solution was 7.5; the concentrations of nicotinamide adenine dinucleotide and lactate dehydrogenase were 1.0 mmol L(-1) and 5.0 k UL(-1), respectively. The linear range of this method was 0.2-1.2 mmol L(-1) (Delta F=327.13C-10.018, r=0.9942). Its detection limit was 0.012 mmol L(-1). And its relative standard deviation was 0.86%. Only 18 microL of total reaction solution is enough for the detection. P-LE-FCA has some merits such as lower cost, simple operation procedure and micro determination. It has been used for the determination of pyruvic acid content in human urine samples.     

在线扫集-胶束毛细管电动色谱法测定复方氨酚烷胺胶囊中的3种有效成分

以在线扫集-胶束毛细管电动色谱法(Sweeping-MEKC)测定了复方氨酚烷胺胶囊中的马来酸氯苯那敏、咖啡因和对乙酰氨基酚3种有效成分。考察了缓冲溶液pH值、SDS浓度、分离电压及进样时间等对分离效果的影响。优化条件:以未涂层熔融石英毛细管(55 cm×50μm,有效柱长35 cm)为分离柱;环境温度25℃;80 mmol/L十二烷基磺酸钠+20 mmol/L NaH2PO4(pH 2.2)+15%乙腈为缓冲体系,分离电压-20kV,进样时间60 s(H=20.0 cm),测量波长210 nm。在该条件下氯苯那敏、咖啡因和对乙酰氨基酚在25min内出峰,峰面积RSD均小于4%;线性范围分别为2.45～39.17、1.61～25.76、1.58～25.28 mg/L;检出限(S/N=3)分别达139、34、24μg/L,回收率分别为96%～101%、98%～102%、96%～102%。