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。     

Nonaqueous capillary electrophoresis with laser-induced fluorescence detection: a case study of comparison with aqueous media

A novel method based on separation by nonaqueous capillary electrophoresis (NACE) combined with laser-induced fluorescence (LIF) detection was developed and compared with classic aqueous modes of electrophoresis in terms of resolution of solutes of interest and sensitivity of the fluorescence detection. Catecholamines derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) were chosen as test analytes for their subtle fluorescence properties. In aqueous systems, capillary zone electrophoresis (CZE) was not suitable for the analysis of test analytes due to complete fluorescence quenching of NBD-labeled catecholamines in neat aqueous buffer. The addition of micelles or microemulsion droplets into aqueous running buffer can dramatically improve the fluorescence response, and the enhancement seems to be comparable for micellar electrokinetic chromatography (MEKC) and microemulsion electrokinetic chromatography (MEEKC). As another alternative, NACE separation was advantageous when performing the analysis under the optimum separation condition of 20 mM sodium tetraborate, 20 mM sodium dodecyl sulfate (SDS), 0.1% (v/v) glacial acetic acid, 20% (v/v) acetonitrile (ACN) in methanol medium after derivatization in ACN/dimethyl sulfoxide (DMSO) (3:2, v/v) mixed aprotic solvents containing 20 mM ammonium acetate. Compared with derivatization and separation in aqueous media, NACE-LIF procedure was proved to be superior, providing high sensitivity and short migration time. Under respective optimum conditions, the NACE procedure offered the best fluorescence response with 5-24 folds enhancement for catecholamines compared to aqueous procedures. In addition, the mechanisms of derivatization and separation in nonaqueous media were elucidated in detail.     

非水胶束电动色谱分离邻苯二甲酸酯类化合物

非水胶束电动色谱(NAMEKC)兼具非水毛细管电泳的优点和胶束电动色谱的分离机制,尤其适于对强疏水性化合物进行分离分析。在以甲酰胺为非水溶剂的电泳介质中,采用十二烷基硫酸钠（SDS）形成胶束相,开展NAMEKC方法的研究。通过添加水溶液、调节水溶液酸度、添加有机溶剂、改变SDS浓度等操作条件的考察,在15 min 内实现了3种美国环保局优先监测的污染物——邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯的分离。分离度最小者为1.5,检测限优于3.04 mmol/L(以信噪比为3计)。3种典型的强疏水性物质的成功分离,显示出NAMEKC方法在分离疏水性物质方面的优势,扩展了NAMEKC在电中性有机物分析中的应用。     

连花清瘟胶囊中6种有效成分的毛细管胶束电动色谱法测定

建立了毛细管胶束电动色谱法同时测定中药复方制剂连花清瘟胶囊中甘草苷、芦丁、金丝桃苷、槲皮苷、绿原酸、大黄酸6种药效成分含量的分析方法.使用未涂层弹性石英毛细管,以50 mmol/L SDS-15mmol/L磷酸氢二钠-15 mmol/L硼酸(含25%异丙醇,pH=8.0)作电解质,于254 nm下紫外检测,被测组分在3...     

胶束毛细管电泳法同时测定消栓通络片中5种有效成分

建立了胶束毛细管电泳法同时测定中药复方制剂消栓通络片中芦丁、丹参素、人参皂苷Rg1、人参皂苷Rb1、三七皂苷R1含量的分析方法。研究了缓冲体系的浓度、添加剂种类、分离电压、进样时间对组分分离的影响,以60 mmol/L SDS-30 mmol/L Tris-10 mmol/L硼酸(含15%甲醇)作运行缓冲液,检测波长214 nm,5种组分在26 min内得到基线分离。芦丁、丹参素、人参皂苷Rb1、人参皂苷Rg1、三七皂苷R1的质量浓度分别在2.5～100、2.5～200、10～300、15～400、15～400 mg/L范围内与其峰面积呈良好的线性关系,检出限分别为0.3、0.9、3.0、5.0、6.0 mg/L。样品在低、中、高3个浓度下的加标回收率为93%～108%,相对标准偏差均不大于4.5%。该方法简便、快速,可用于实际样品检测。     

On-line pretreatment and determination of parabens in cosmetic products by combination of flow injection analysis, solid-phase extraction and micellar electrokinetic chromatography

A convenient and automated method for on-line pretreatment and determination of three parabens (i.e. methyl, ethyl and propyl p-hydroxybenzoate) in cosmetic products is proposed by using flow injection analysis (FIA), solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC). An improved split–flow interface is used to couple SPE on C₈-bonded silica with MEKC separation, which can avoid running buffer contamination and reduce buffer consumption, especially, containing expensive reagents. The analytes are loaded onto a C₈ column at 0.6 mL/min for 60 s and eluted with a mixed eluent of 40% (v/v) 10 mmol/L sodium tetraborate buffer (pH 9.3) and 60% (v/v) ethanol at 0.75 mL/min. The MEKC separation is accomplished with a running buffer of 20 mmol/L sodium tetraborate (pH 9.3) containing 100 mmol/L sodium dodecyl sulfate (SDS) at 15 kV. For butyl p-hydroxybenzoate did not be detected in the cosmetic products, it was used as an internal standard (IS) added into the real samples. This FIA–SPE–MEKC method using IS allows the sample separation within 12 min and the sample throughput of five samples per hour with the relative standard deviation (R.S.D.) less than 2.3% (n = 5). The limits of detection (LOD) are in the range from 0.07 to 0.1 μg/mL (S/N = 3 and n = 11). The proposed method has been used to determine three parabens in real cosmetic products satisfactorily.     

Rapid and sensitive analysis of three polyphenols in tobacco by CE using homemade C(4) D with a mini detection cell

A rapid, sensitive, and practical CE with C(4) D detection was developed for the analysis of three polyphenols (rutin, scopoletin, and chlorogenic acid) in tobacco samples. The constructed mini detection cell (12 mm × 10 mm × 10 mm) of C(4) D featured with small inner cell volume (～2 nL), smaller noise (<0.9 mV), repeatability, high strength and durableness. Three polyphenols were ultrasonically extracted with methanol-water (70:30, v/v) solution following SPE cleanup. The CE method was optimized with the running buffer of 150 mmol L(-1) 2-amino-2-methyl-1-propanol (pH 11.2), and the applied separation voltage of +20 kV over a capillary of 50 μm id × 375 μm od × 50 cm (38 cm to the C(4) D window, 41.5 cm to the UV detector window), which gave a baseline separation of three polyphenols within ca. 6 min. The method provided the limits of quantification (S/N = 10) at about 0.08-0.15 μg g(-1) for three polyphenols, whereas the overall recoveries ranged from 82% to 88%. The proposed method has been successfully applied to measure three polyphenols in the actual tobacco samples, and their contents were calculated and evaluated.     

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。     

胶束电动毛细管色谱法同时测定复方化学消毒剂及日化产品中邻苯二甲醛、对氯间二甲基苯酚及三氯生

建立了邻苯二甲醛(OPA)、对氯间二甲基苯酚(PCMX)和三氯生3种杀菌剂同时分离测定的胶束电动毛细管色谱(MEKC)新方法。详细研究了影响上述3种杀菌剂同时分离与准确定量的因素: 如分离缓冲溶液的浓度及pH,十二烷基硫酸钠(SDS)浓度、样品缓冲溶液等。以40.2 cm (有效长度: 30 cm)×50 μm未涂层熔融石英毛细管为分离柱,20 mmol/L硼砂-80 mmol/L SDS(无需调pH)为分离缓冲溶液,2 mmol/L硼砂-8 mmol/L SDS (含体积分数为10%甲醇)为样品缓冲溶液,检测波长为214 nm。3种杀菌剂的校正峰面积的相对标准偏差(RSD)在1.1%～ 3.8%范围内,迁移时间的RSD均小于0.9%, OPA、PCMX和三氯生的检出限(LOD,信噪比为3)分别为4.0、0.4、0.4 mg/L,定量限(LOQ,信噪比为10)分别为12、1.2、1.2 mg/L,校正峰面积与相应的质量浓度分别在12～2 000 mg/L、1.2～200 mg/L和1.2～200 mg/L范围内具有良好的线性关系,相关系数分别为0.9994、0.9993和0.9995。该法前处理简单,可快速、准确地同时测定3种组分,非常适合常规实验室分析。     

Comparison of enantioseparation of amino acid derivatives in aqueous and mixed aqueous-organic media by capillary zone electrophoresis

The chiral separation of dansyl-amino acids has been performed by capillary zone electrophoresis using ¶β-cyclodextrin as a chiral selector, urea as an additive and 2-propanol and methanol as organic modifiers. The enantiomeric separations of dansyl-amino acids were investigated in aqueous medium and compared with the separation in mixed aqueous-organic medium as background electrolytes. The separation conditions, (concentration of buffer, β-cyclodextrin, methanol, urea and the pH value of buffer) were optimized. In the absence of organic modifier, only five pairs of 8 separated dansyl-amino acids were resolved when run separately. A mixture of up to eight chiral amino acids can be baseline resolved in less than 19 min by β-cyclodextrin-modified capillary zone electrophoresis with a buffer of 60 mmol L^–1 H₃BO₃-KCl/40 mmol L^–1 NaOH (pH 9.0), 4 mol L^–1 urea, 100 mmol L^–1β-cyclodextrin and 10% (v/v) methanol.     

Electrophoretic separation with 2-mm inner diameter fused-silica microcolumn packed with quartz microncrystals and its application

The feasibility of a microcolumn electrophoresis technique was investigated with a 100 mm length, 2 mm I.D. fused-silica microcolumn packed with uniform quartz microncrystals prepared by hydrothermal synthesis. To evaluate the separation technique, tryptophan, phenylalanine and tyrosine were primarily separated by the microcolumn electrophoresis and detected at 216 nm without derivatization by an ordinary spectrophotometer. The separation conditions of the amino acids were optimized. With 1.5 mmol/L disodium phosphate buffer solution (pH 11.5) containing 25% (v/v) methanol and 10% (v/v) acetonitrile, the three amino acids were separated and the separation efficiency of tryptophan was 4.5 × 10⁴ plates/m. The limits of detection were 0.035, 0.22 and 0.20 μmol/L, respectively. The sample capacity of the electrophoretic microcolumn achieved 35 μL. The proposed method was used to determine these amino acids in compound amino acid injection samples without derivatization. For the simplicity and portability of the microcolumn electrophoresis, it is studied as one of the high-performance separation techniques for an in situ and real-time electrokinetic flow analysis system. For its high detection sensitivity and large sample capacity, it can be developed for preparative electrophoresis.     

Nonaqueous capillary electrophoresis in coated capillaries: an interesting alternative for proteomic applications

This work brings together some contributions for the use of nonaqueous media for proteomic analysis, for both capillary electrophoresis (CE) separation and the preparation of tryptic digests. First, a ternary nonaqueous buffer consisting of 60/30/10 v/v methanol/acetonitrile/acetic acid with 12.5 mmol/L ammonium acetate was optimized for CE separation of the tryptic digest of lysozyme. Lysozyme was chosen as a model system for the protein digestion, which has also been prepared in an organic-rich medium with methanol/50 mmol/L NH(4)HCO(3), pH 8.0 (60/40 v/v). The separation results were compared to in silico (PeptideCutter program) digestion conditions, and high-efficiency peak separation (18 peaks) was obtained in 20 min with an electric field of 350 V/cm. In addition, we have evaluated the stability of a coated capillary with poly-N,N-dimethylacrylamide (60/30 cm total/effective length and 75 microm ID) for over 100 runs of tryptic digest with the nonaqueous background electrolyte solvent system. The migration times for ten selected peptide peaks presented 3-7% relative standard deviation.     

Determination of seven polyphenols in water by high performance liquid chromatography combined with preconcentration

A method for determination of seven polyphenols (chlorogenic acid, esculetin, caffeic acid, scopoletin, rutin, quercetin hydrate, kaempferol) by reversed-phase high performance liquid chromatography (RP-HPLC) combined with preconcentration was developed. The preconcentration was accomplished by adsorption-desorption method with a styrene-divinylbenzene resin (XAD-4), and the analytes were desorbed by methanol. The parameters of adsorption and desorption, such as the amounts of resin, adsorption time, pH of the adsorption solution, and the volume of methanol for desorption were optimized. RP-HPLC with photodiode array detector (PAD) was employed for the qualitative and quantitative analysis. Methanol and acetic-water (1:99, v/v) solution were used as the mobile phase, and a gradient program was established for separation. Calibration curves of the seven analytes were obtained in the range of 0.8-3 mg L⁻¹, with correlation coefficients (R) higher than 0.9990. With standard samples, the recoveries for the preconcentration step under optimal conditions were 93-99%, and the relative standard deviations were 0.2-2.0% (n = 5). Polyphenols in simulated tobacco-polluted water were analyzed with the optimized conditions. Chlorogenic acid and rutin were found and determined, whose concentrations were 32.8 and 19.2 μg L⁻¹, respectively. The spiked recoveries of the polyphenols were 83-95% except quercetin hydrate (63%), the relative standard deviations were less than 3.5% (n = 5).     

胶束电动毛细管色谱法同时测定西洋参中人参皂苷Rg1、Re和Rb1

建立了西洋参中人参皂苷Rg1、Re及Rb1同时分离测定的胶束电动毛细管色谱新方法,以解决西洋参样品中难溶于水的3种人参皂苷的准确定量问题。以40.2 cm(有效长度30 cm)×50 μm的熔融石英毛细管柱为分离柱,分离缓冲液的组成为V(15 mmol/L Na2B4O7+30 mmol/L H3BO3 (pH 9.0)+100 mmol/L十二烷基硫酸钠(SDS)+30 g/L聚乙二醇35000):V(甲醇):V(异丙醇)=2:1:1,于214 nm下检测。详细研究了影响分离的因素。Rg1、Re及Rb1检出限(信噪比(S/N)为3)分别为30、40及30 mg/L,定量限(S/N=9)分别为90、120及90 mg/L,加标回收率为87.4%～95.2%。用该法测定了西洋参标准物质,并与高效液相色谱法的检测结果进行了比对,结果吻合。应用该方法分别测定了中国、加拿大及美国的西洋参,获得满意的结果。     

胶束电动毛细管色谱法分析玫瑰纯露中的苯乙醇

玫瑰纯露是玫瑰提取精油后的重要副产物,是玫瑰精油的饱和水溶液,不仅含有植物水溶活性成分,同时也保留了精油的芳香成分,含有矿物养分,具有抗衰老、清除自由基,抗过敏、抗菌、消炎、防紫外线损伤等功效,是继玫瑰精油之后护肤领域重要的优势产品之一,但目前尚无关于其质量控制的标准,市售产品质量参差不齐。为此,该研究发展了一种胶束电动毛细管色谱法用于快速检测玫瑰纯露中的指标成分苯乙醇。在实验过程中分析物的定性通过标准物质加标及紫外吸收可见光谱图比对确认。实验对缓冲溶液中硼砂浓度、十二烷基硫酸钠（SDS）浓度、分离电压、进样条件、检测条件等影响检测的关键因素进行了考察。在优化条件（分离缓冲溶液10 mmol/L Na₂ B₂ O₇ +15 mmol/L SDS,分离电压+20 kV,检测波长208 nm,进样5 kPa,5 s）下,玫瑰纯露样品在7 min内可以完成检测。本方法对苯乙醇检测的线性范围为0.50~1000 mg/L,线性相关系数（r ² ）为0.9990,检出限（LOD,S/N =3）为0.091 mg/L,定量限（LOQ,S/N =10）为0.35 mg/L,实际样品加标回收率为98.1%~102.7%（加标水平10、100、500 g/L）,相对标准偏差（RSD）≤2.8%。结果表明,该方法为玫瑰纯露及其制品的质量控制提供了一种简便、快速、灵敏、稳定的分析方法。     

毛细管电泳法测定桑叶中的黄酮类成分──芦丁和槲皮素

 采用高效毛细管电泳法分离测定了新疆不同地区、不同采集期、不同品种的桑叶中的黄酮类成分芦丁、槲皮素的含量。以含有体积分数为 15 %甲醇的 10mmol/L的磷酸二氢钠 2 0mmol/L的硼砂溶液 (pH 8 6 2 )为电泳缓冲液 ,采用压力进样方式 ,在 2 5℃ ,2 0kV恒压下进行电泳分离 ,并在 2 45nm波长处检测。结果表明 ,桑叶中的两种目标组分在 12min内完全分离 ,且有良好的线性关系 ;芦丁和槲皮素的加样回收率分别为 95 6 4%和99 36 % ,其RSD分别为 2 2 5 %和 1 79% (n =6 )。方法简单、准确、快速。     

高效毛细管电泳法测定二氢叶酸还原酶活力的研究

通过胶束电动毛细管电泳法研究分离二氢叶酸还原酶体系中二氢叶酸、四氢叶酸、 NADP、 NADPH和酶5种组分,在含0.002%Brij-35的pH 9.18 50 mmol/L 的硼砂缓冲溶液中,5种组分在18min内得到基线分离.通过对其产物四氢叶酸峰面积的定量测定,计算出二氢叶酸还原酶的米氏常数,建立了毛细管电泳法对二氢叶酸还原酶活力的测定方法.     

Determination of scopolamine, atropine and anisodamine in Flos daturae by capillary electrophoresis.

A capillary electrophoresis method was developed for the separation and determination of tropane alkaloids in Flos daturae plants. Separation was performed on a fused silica capillary(42.1 cm x 50 microm i.d.) at an applied voltage of 20 kV. Scopolamine, atropine and anisodamine were well separated in the buffer of 50 mmol/L phosphate buffer (pH 5.0) containing 20% (v/v) tetrahydrofuran (THF). Beer's law was obeyed in the range of concentration of 2.4-21.8 microg/mL for scopolamine, 4.0-36.0 microg/mL for atropine and 2.6-23.7 microg/mL for anisodamine, respectively, and the correlation coefficients were over 0.999 (n = 6). The developed method was applied for the analysis of herb samples.     

Effect of diluting agent on sensitivity in capillary electrophoresis with amperometric detection

Besides the running buffer, pH of buffer, separation voltage and sampling time, the diluting agent was studied in this paper as one of the important factors influencing the sensitivity in capillary electrophoresis (CE) with amperometric detection (AD) when electrokinectic sampling was used. Clonidine hydrochloride, hydrochlorothiazide and rutin, which are positively charged, neutral and negatively charged, respectively, in aqueous solutions, could be perfectly separated by CE with 25 mmol x L(-1) Na(2)B(4)O(7) - 50 mmol x L(-1) NaH(2)PO(4) as running buffer and detected by measuring their current responses with AD. Before CE running, some kinds of diluents including water, methanol, formamide, running buffer, hydrochloric acid and sodium hydroxide were, respectively, applied to dilute the stock solutions of above three analytes and their effects on the sensitivity of CE-AD were investigated. The results showed that for electrokinetic injection, the current responses of these three analytes were greatly affected in different ways when different diluting agents were used. This method was applied to simultaneously determine the active ingredients in one Chinese compound hypotensor named Zhen Ju Jiang Ya Pian, in which the contents of clonidine hydrochloride, hydrochlorothiazide and rutin is very different as 0.03 mg : 5 mg : 20 mg per tablet, and satisfactory results were obtained by adjusting their sensitivity by selecting the suitable diluting agent.     

Capillary electrophoresis direct enantioseparation of aromatic amino acids based on mixed chelate-inclusion complexation of aminoethylamino-beta-cyclodextrin

6(A)-(2-Aminoethylamino)-6(A)-deoxy-beta-cyclodextrin (CDen) was synthesized and formed a binary complex with Cu(II) which was shown to be an effective chiral selector for separation of underivatized amino acid enantiomers in capillary electrophoresis (CE). Moreover, the chiral resolution was greatly enhanced by the presence of polyethyl glycol (PEG) and tert-butyl alcohol in the running buffer. The optimum experimental conditions were 20 mmol/L CDen, 20 mmol/L CuSO(4).5H(2)O, 5.0 mg/mL PEG20000 and 1.0% v/v tert-butyl alcohol, pH 5.80. With the proposed method, the four selected aromatic chiral amino acid pairs were separated in less than 15 min.