毛细管电泳-激光诱导荧光用于中药制剂中氨基酸成分的分析

建立了一种用于测定中药制剂中氨基酸成分的毛细管电泳-荧光检测方法. 用含有α-环糊精(α-CD)的硼砂缓冲溶液为背景电解质, 经异硫氰酸荧光素(FITC)衍生的5种氨基酸在50 min内可以得到很好的分离和测定. 考查了各个分离参数对分离的影响, 得到的优化条件为: 含45 mmol/L的α-环糊精的80 mmol/L硼砂缓冲溶液(pH值9.2)作为背景电解质, 分离电压20 kV; 柱温22 ℃. 衍生试剂FITC与单个氨基酸的化学计量比为4∶1时, 能够获得稳定荧光强度的氨基酸衍生物. 在优化条件下, 各氨基酸成分在73.5～2900 nmol/L 的浓度范围内呈良好的线性关系(相关系数r2为0.9906～0.9998). 保留时间和峰面积的相对标准偏差分别为0.8%～3.0%和0.7%～5.7%, 检测限(3倍信噪比)为3.5～35 nmol/L. 该方法准确可靠, 可用于质量控制为目的的中药制剂中氨基酸成分的定量测定.     

气相色谱法测定茶叶中邻苯二甲酸酯

建立了同时检测茶叶中5种邻苯二甲酸酯类(PAEs)的气相色谱(GC)-氢火焰离子(FID)检测方法,并对市售部分茶叶中的PAEs含量进行了测定。茶叶样品采用同时蒸馏萃取,处理后以HP-5石英毛细管柱分离,GC-FID法进行检测,外标法定量。5种PAEs在各自检测浓度范围内线性关系良好,其线性相关系数均达到0.999以上,检出限(LOD)为2.63~8.42μg/L,加标回收率在78.2%~111.3%之间,相对标准偏差(RSD)均小于5%,方法可以满足实际茶叶样品中5种PAEs的分析检测。     

毛细管电泳法测定阿霉素脂质体药物中的微量硫酸根离子

建立了以硝酸钾作为背景电解质测定阿霉素脂质体药物中微量硫酸根离子的毛细管电泳分析法。考察了分离电压、背景电解质、电渗流改性剂浓度、pH值对分离测定的影响。结果表明,当毛细管长度为60 cm(有效长度51.5 cm)、分离电压为~15 kV、缓冲溶液采用20 mmol/L硝酸钾(pH 7.0)、电渗流改性剂采用0.4 mmol/L十六烷基三甲基氯化铵(CTAC)、检测波长为202 nm时,阿霉素脂质体破乳液中硫酸根离子和氯离子在3 min内得到了基线分离,硫酸根离子迁移时间和峰面积的相对标准偏差分别小于0.01%和1.0%,检出限为5 μg/L。用该方法对阿霉素脂质体样品中的微量硫酸根离子进行了分析测定,结果令人满意。     

单纯形算法动态优化毛细管胶束电动色谱分离体系

采用控制加权可变步长单纯形算法对ＰＴＣ氨基酸的毛细管胶束电动色谱分离体系进行动态优化。寻优过程中同时考虑背景电解质的ｐＨ值、十二烷基硫酸钠浓度和有机添加剂浓度对体系分离效果的影响。分别使用Ｌｏｎｇ系数法和均匀设计表法确定初始单纯形顶点对分离体系进行动态优化。优化结果使１７种ＰＴＣ氨基酸获得了比较满意的分离。     

毛细管电动色谱带电环糊精拆分N-FMOC氨基酸对映体

 将负电性磺丁基 -β -环糊精手性添加剂应用于毛细管电泳氨基酸对映体的拆分研究中 ,对 8种氨基酸对映体与 9-芴甲基氧基甲酰氯 (FMOC-Cl)生成的衍生物进行了分离 ,其中 5种得到了基线分离。考察了背景电解质 p H值及磺丁基 -β -环糊精的浓度对 N-FMOC氨基酸对映体拆分的影响。     

茶叶中无机阴离子的毛细管电泳分离间接检测方法的研究

建立了毛细管电泳分离测定茶叶中Cl-、NO2-、NO3-、SO42-、F-及HPO24-的方法。通过研究分离电压、背景电解质和电渗流改性剂的浓度、pH的影响优化了分析条件。在优化条件下,6种无机阴离子在10min内得到完全分离,各组分迁移时间和峰高的相对标准偏差(RSD)分别为1.9%~4.7%和1.2%~3.8%,检出限为0.11~0.82 mg/L。通过分析实际样品并做加标回收实验验证了该方法的可行性,Cl-、NO3-、SO42-及HPO24-的回收率为93%~98%。     

UPLC-MS/MS测定铁观音茶中21种游离氨基酸含量

建立了一种高效、快速可直接测定茶叶中21种游离氨基酸的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。茶叶样品经粉碎、超声提取、离心净化、定容后,采用Capcell Pak C18柱(5μm, 2.1×150mm)进行梯度洗脱分离,流动相为0.3%甲酸水溶液-乙腈,流速0.4mL·min~(-1)。茶叶中21种游离氨基酸在7.2～335.5ng·mL~(-1)范围内的线性关系良好(R~2≧0.996),检出限0.1～3.8 mg·kg~(-1),定量限0.4～12.5 mg·kg~(-1),加标回收率72.1%～104.2%,相对标准偏差RSD≦5.3%(n=6)。该方法分析速度快、灵敏度高、选择性好,适用于茶叶中21种游离氨基酸的快速检测和定量分析。     

水溶性β-CD聚合物在毛细管电泳中分离氨基酸对映体

以环氧氯丙烷（EP）为交联剂,合成水溶性的β-环糊精聚合物（β-CDpoly-met）,提出了一种以β-CDpolymer为手性选择剂,在毛细管电泳中分离未衍生芳环氨基酸对映体的方法。考察了手性选择剂浓度、背景电解质溶液pH、柱温及分离电压对分离的影响。在优化的实验条件下,使3种氨基酸对映体得到了基线分离。     

毛细管电泳法手性拆分达卢生坦中间体2-羟基-3-甲氧基-3,3-二苯基丙酸

建立了毛细管电泳法拆分2-羟基-3-甲氧基-3,3-二苯基丙酸的方法.考察了背景电解质的pH值和浓度、手性选择剂的种类及浓度、有机改性剂种类及浓度对分离的影响,并对分离条件进行了优化.实验结果表明,在60 mmol/L磷酸氢二钠(pH=9.10)为运行缓冲溶液,舍35.7 mmol/L羟丙基-β-环糊精和5%甲醇的体系...     

毛细管电泳-电容耦合非接触电导检测法对运动员营养补剂中人体必需支链氨基酸的检测

建立了运动员营养补剂中3种人体必需支链氨基酸(缬氨酸、亮氨酸、异亮氨酸)的毛细管电泳-电容耦合非接触电导检测(CE-C4D)测定方法。通过研究电泳时背景电解质种类、浓度以及电导检测器的激发电压,激发频率等参数的影响,确定最佳的实验条件为采用未涂层熔融石英毛细管(60 cm×75μm,有效长度50 cm),以5.0 mol/L的乙酸为背景电解质;C4D检测器激发电压为40 V,激发频率为600 kHz;运行电压为+15 kV,温度为25℃。3种氨基酸在50.0~1000.0μmol/L范围内线性关系良好,线性相关系数(R2)均大于0.9994,加标回收率在98.6%~105.4%之间,方法的检出限为14.88μmol/L。方法已应用于运动员蛋白营养补剂中的支链氨基酸的测定。     

Determination of amino acids in tobacco samples by capillary electrophoresis/indirect absorbance detection with isolation of the electrolysis compartment and p-Aminobenzoic acid as a background electrolyte.

A fast, convenient and sensitive method of capillary zone electrophoresis (CZE) and indirect UV detection was proposed for the determination of 16 amino acids. p-Aminobenzoic acid (PAB) was selected as a background electrolyte (BGE). An isolated cell included a BGE buffer part and an electrode buffer one, which were jointed with a glass frit. The isolated cell can prevent PAB from the electrode reaction and improve the stability of the detection baseline. The separation conditions of amino acids were investigated, such as different BGEs, BGE concentration, buffer pH and electroosmotic flow (EOF) modifiers. Under the selected separation conditions, 14 amino acid peaks could be separated in 12 min. The detection limits of the amino acids were in the range of 1.7 - 4.5 micromol/L. The isolated cell is suitable for reagents reacting on the electrodes in capillary electrophoresis. The proposed method has been successfully applied to the determination of the amino acids in tobacco samples.     

Analysis of organic acids and inorganic anions in beverage drinks by capillary electrophoresis

To meet the need for a new and validated analytical method for simultaneous determination of inorganic and organic acid anions in beverage drinks, a capillary zone electrophoresis (CZE) procedure had been developed based on a new background electrolyte (BGE) system containing 3 mmol/L 1,3,5-benzenetricarboxylic acid (BTA), 15 mmol/L tris(hydroxymethyl)aminomethane and 1.5 mmol/L tetraethylenepentamine (TEPA) at pH 8.4. Baseline separation of anions commonly found in beverage drinks could be achieved in less than 14 min with indirect UV detection at 240 nm. Comigration problems for hydroxycarboxylic acids could be solved using TEPA as BGE additive. The results indicate excellent repeatability for migration time (RSD, 0.27-0.67%, n = 5) and good precision for both peak height (RSD, 3.2-4.2%, n = 5) and peak area (RSD, 3.1-4.5%, n = 5). Under the optimized conditions and using corrected peak area for quantitation, an excellent linear dynamic range (with correlation coefficient > 0.997 in a concentration range from 0.005 to 2.0 mmol/L) and low detection limit (1-4 micro mol/L) were obtained for all the anions investigated. The applicability and reliability of the CE procedure developed were established by parallel method determination using established ion chromatography procedure for the analysis of inorganic and organic acid anions in orange juice and wine samples. Our CZE procedure provided a sensitive and economic technique for simultaneous determination of inorganic and organic acid anions in orange juice, red and white wine samples.     

Direct UV detection of underivatized amino acids using capillary electrophoresis with online sweeping enrichment

This is an original report proposed a CE method for direct analysis of the underivatized amino acids using UV detection with relatively higher sensitivity, which was based on coordination interactions between amino acids and Cu (II) ions. In addition, an online sweeping preconcentration technique was easily combined to improve the detection sensitivity. Satisfying separations of the amino acids were obtained under optimized conditions: 50 mmol/L CuSO₄–0.05% HAc–H₂O (pH 4.5), and the separation voltage of 15 kV. The LODs for the analytes ranged from 0.1 to 0.5 μmol/L. The linearity of detection for all analytes was two orders of magnitude with the correlation coefficients greater than 0.99. The repeatability was displayed with an RSD less than 3% for migration time and peak height (n = 5). Moreover, some amino acids in real samples of human saliva and green tea were analyzed by this direct UV detection CE method with acceptable sensitivity.     

High‐speed separation and detection of amino acids in laver using a short capillary electrophoresis system

A high‐speed separation method of capillary MEKC with LIF detection had been developed for separation and determination of amino acids in laver. The CE system comprised a manual slotted‐vial array (SVA) for sample introduction that could improve the separation efficiency by reducing injection volume. Using a capillary with 80 mm effective separation length, the separation conditions for amino acids were optimized. Applied with the separation electric field strength of 300 V/cm, the ten amino acids could be completely separated within 2.5 min with 10 mol/L Na₂HPO₄–NaOH buffer (pH = 11.5) including 30 mmol/L SDS. Theoretical plates for amino acids ranged from 72 000 to 40 000 (corresponding to 1.1–2.0 μm plate heights) and the detection limits were between 25 and 80 nmol/L. Finally, this method was applied to analyze the composition of amino acids in laver and eight known amino acids could be found in the sample. The contents of five amino acids, tyrosine, glutamic acid, glycine, lysine, and aspartic acid that could be completely separated in real sample were determined. The recoveries ranged from 82.3% to 123% that indicated the good reliability for this method in laver sample analysis.     

Determination of amino acids in tea leaves and beverages using capillary electrophoresis with light-emitting diode-induced fluorescence detection

The combination of capillary electrophoresis (CE) and light-emitting diode-induced fluorescence (LED-IF) detection has been demonstrated in the analysis of major amino acids in tea leaves and beverages. The separation efficiency of amino acids, which were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA), depended on the capillary length and PEO concentration. We suggested that the interactions between the NDA derivatives and poly(ethylene oxide) (PEO) molecules are based on hydrogen bonding, hydrophobic patches, and Van der Waals forces. The magnitude of EOF and the interactions between them can be further controlled by the capillary length. The separation of 17 NDA-amino acids derivatives was completed within 16 min using 0.5% PEO and 60 cm capillary length. The relative standard deviations (R.S.D.) of their migration times (n = 5) were less than 2.7%. Additionally, the limits of detection at signal-to-noise ratio 3 for the tested amino acids ranged from 3.6 to 28.3 nM. Quantitative determination of amino acids in tea leaves and beverages was accomplished by our proposed method. This study showed that amino acid present in highest concentration in tea leaves and beverages is γ-aminobutyric acid and theanine, respectively. The experimental results suggest that our proposed methods have great potential in the investigation of the biofunction of different tea samples.     

超高效液相色谱-串联质谱法测定茶叶中游离氨基酸成分

建立了使用超高效液相色谱-串联质谱（UHPLC-MS/MS）高效、快速直接测定茶叶中游离氨基酸的方法。通过对质谱、色谱条件及氨基酸提取条件的优化，以含0.2%（体积分数）甲酸的5 mmol/L乙酸铵水溶液和甲醇为流动相进行梯度洗脱，在电喷雾离子（ESI）源正离子扫描模式下检测，通过UHPLC-MS/MS测定，共解析了茶叶中的20种氨基酸。结果表明，茶氨酸（Thea）、Arg、Asn和Asp在50~500 μg/L范围内线性关系良好，其他氨基酸在10~250 μg/L范围内线性关系良好，相关系数均大于0.99；加标回收率为92.3%~109.2%，相对标准偏差为2.00%~9.88%，检出限为0.001~0.011 mg/L，定量限为0.010~0.053 mg/L。该方法灵敏、准确，具有良好的重复性和稳定性，可有效检测出茶叶中的20种氨基酸及氨基类成分。     

毛细管电泳柠檬酸-Zn2+体系对异亮氨酸对映体的手性分离

应用毛细管电泳/电容耦合非接触式电导（CE-C⁴D）分离检测技术,研究了柠檬酸-Zn²⁺体系对异亮氨酸对映体的手性识别行为。结果表明,采用未涂层石英毛细管（45 cm×50 μm,L_eff=40 cm）,以2.8 mmol/L NaOH+0.8 mmol/L柠檬酸+2.0 mmol/L乙酸锌为非手性介质电泳运行液,分离电压+13 kV,D,L-异亮氨酸对映体得到了良好的手性识别,对映体分离度达到2.0。线性检测范围为1.0~20 mg/L,检出限（S/N=3）为0.40 mg/L。对影响分离度的因素（Zn²⁺的浓度、电泳运行液的组成、分离电压以及其他氨基酸的干扰情况等）进行了详细的讨论,并对手性识别机理作了初步探讨。     

非衍生化毛细管区带电泳直接紫外检测法测定茶叶中的4种氨基酸

采用非衍生化毛细管区带电泳直接紫外检测法同时分离测定精氨酸(Arg)、色氨酸(Trp)、苯丙氨酸(Phe)和酪氨酸(Tyr)4种氨基酸,并应用于不同发酵过程的茶叶样品的测定。在分离电压为20 kV、柱温为25 ℃、检测波长为190 nm条件下,以25 mmol/L硼酸-硼砂缓冲溶液(pH 10.0)为运行缓冲液,4种组分在8 min内达到基线分离,Arg、Trp、Phe、Tyr的检出限分别为5.0,1.0,0.3和0.5 mg/L。7次平行测定中,4种组分迁移时间的相对标准偏差(RSD)均小于2.8%,峰电流的RSD均小于4.0%。将所建立的方法用于11种实际茶叶样品中Arg、Trp、Phe和Tyr含量的测定,结果令人满意。该方法可以为茶叶的质量评估提供借鉴。     

Determination of Amino Acidsas Their N-Hydroxy-succinimidyl-3-indolylacetate Derivatives by Reversed-phase HPLC

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