毛细管区带电泳法测定低卡路里食品中甜菊苷

1　引　　言当前 ,食用传统糖源已是造成肥胖、糖尿病以及心血管等疾病的重要原因之一。甜菊糖苷 (主要成分为ｓｔｅｖｉｏｓｉｄｅ(Ｓｔ)和ｒｅｂａｕｄｉｏｓｉｄｅＡ(ＲＡ) )作为高甜度低热能的理想甜味剂 ,广泛用于食品和医药行业。本文通过对甜菊苷标样中两种主要成分Ｓｔ和ＲＡ的分离分析 ,探讨了进样量、电压、柱温、缓冲液浓度以及ｐＨ值等条件对其分离效果的影响 ,建立用毛细管电泳定量测定低卡路里食品中甜菊糖苷含量的快速、灵敏、高效的新方法。2　实验部分2 .1　仪器和试剂　ＣＥ30 0 0型毛细管电泳仪 (Ｂｉｏ Ｒａｄ ,ＵＳＡ)…     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱非靶标筛查测定白酒和饮料中甜菊糖苷

建立了亲水作用色谱-超高效液相色谱-四极杆/静电场轨道阱质谱非靶向筛查测定白酒和饮料中甜菊糖苷的分析方法，并对甜菊糖苷类天然甜味剂的质谱裂解规律进行了研究。样品经水溶液适当稀释，过滤膜后经Waters Xbridge Amide色谱柱（150 mm×4.6 mm，3.5 μm）分离，超高效液相色谱-四极杆/静电场轨道阱质谱检测，电离模式为电喷雾电离源负离子模式，数据采集使用一级母离子全扫描和数据依赖的二级子离子扫描（full MS/dd-MS²）模式。基于8种甜菊糖苷标准品的碎片离子谱分析，识别出甜菊糖苷类化合物存在两个共性碎片离子，以这两个离子作为标识离子对样品中未知甜菊糖苷类化合物进行了非靶标筛查。通过方法学验证，8种甜菊糖苷标准品在10~1000 μg/L内线性关系良好，检出限为0.3~20 μg/L。添加量为10~100 μg/kg时，平均回收率为81.9%~106%，相对标准偏差为0.1%~9.3%（n=3）。该方法筛查范围广，结果准确，灵敏度高，可用于食品中甜菊糖苷的非靶标筛查测定。     

HPLC-MS/MS同时检测5种甜菊糖苷类化合物

应用HPLC-MS/MS法同时检测了食品中5种甜菊糖苷类化合物:甜菊糖甙,瑞鲍迪甙A,瑞鲍迪甙C,杜克甙A和甜菊双糖甙的含量。样品用水超声提取,5种甜菊糖苷类化合物的定量限(LOQ)为1.7~3.4 mg/kg,样品在10,50,200 mg/kg添加水平的回收率为78%~107%,相对标准偏差(RSD)为4.9%~11%。方法可用于多种甜菊糖甙苷类的检测。     

重结晶法分离精制莱鲍迪甙A的研究

用甲醇、异丙醇和水不同比例的混合溶剂对甜叶菊糖以及分离出甜菊甙的母液浓缩物分别进行重结晶研究，考察了甜菊甙和莱鲍迪甙A的结晶分离及菜鲍迪甙A结晶纯化的最佳条件，得到了高纯度的莱鲍迪甙A，并对其进行了熔点测定和HPLC表征，为莱鲍迪甙A的分离与纯化提供了一种简便的方法。     

高效液相色谱法分离和测定甜菊甙

〕本文研究了应用反相高效液相色谱法分离甜菊糖甙,对其中主要成分甜菊甙进行了鉴定和定量测定。分析条件如下：柱,YWG-C18H37;流动相,甲醇-水（75:25,体积／体积）;紫外检测波长205nm,甜菊甙最小检知量：0.2μg。分析了18个甜菊糖甙样品,定量测定结果：甜菊甙含量在43.80～60.39%,相对标准偏差为1.6%。     

寡糖的毛细管电泳分析

多种寡糖经α－萘胺衍生化后，用硼砂作为电泳介质，实现了高效毛细管电泳分离。比较了毛细管区带电泳和胶束毛细管电动色谱分离寡糖α－萘胺衍生物的电泳行为，对影响分离度的诸因素进行了考察，选择了最佳分离条件。     

泽泻乙醇提取物的HPCE分离研究

采用高效毛细管电泳的胶束电动毛细管色谱的分离模式(MEKC),对泽泻的乙醇(95％)提取物进行分离研究。以十二烷基硫酸钠(SDS)胶束为准固定相．硼砂为缓冲体系,甲醇为有机添加剂,考察了SDS浓度、硼砂浓度、pH、甲醇用量、电泳电压、电泳温度等对分离的影响。结果表明：硼砂缓冲体系为运行缓冲溶液(pH：9．18～9．20)、硼砂浓度30mmoL／L、SDS浓度45mmol／L、甲醇体积分数30％,分离电压25kv、分离温度25℃时分离效果最好。在此条件下,得到分离度和重现性均较好的泽泻乙醇提取物的HPCE色谱图。     

毛细管电动色谱分离手性氨基酸及其在生物样品分析中的应用

建立了MEKC法分离丙氨酸(Ala)、谷氨酸(Glu)和天门冬氨酸(Asp)三对手性氨基酸,并对大鼠正常组和白内障组晶体和血清中DAla、LAla、DGlu、LGlu、DAsp和LAsp进行定量分析。利用FITC柱前衍生,以β环糊精(βCD)作为手性添加剂,激光诱导荧光检测(LIF),优化电泳条件为气压进样5s,分离温度25℃,分离电压为20kV,运行缓冲溶液为40mmol/L硼砂缓冲溶液(pH9.3),其中包含50mmol/LSDS和13mmol/LβCD。考察了硼砂缓冲溶液浓度、pH值、分离电压、β环糊精浓度对分离的影响。在优化电泳条件下,上述3种氨基酸对映体均得到基线分离,并可对大鼠的晶体和血清进行定量分析。本方法操作简单,检测灵敏度高,可用于药品质量监测以及生物样品的分析。     

毛细管区带电泳分离西孟坦对映异构体

以β-CD为手性选择剂,采用毛细管区带电泳成功分离了西孟坦对映异构体。考察了背景电解质中硼砂缓冲液的pH和浓度、β-CD浓度、有机添加剂甲醇含量及分离电压对手性分离的影响,建立了毛细管电泳分离西孟坦对映异构体的方法。最佳分离条件为：20mmol／L硼砂缓冲液(pH11．0,含12mmol／Lβ-CD)-甲醇(50：50,V/V);分离电压20kV。在此条件下西孟坦对映异构体可达基线分离。在25～50mg／L范围内,迁移时间的重复性(RSD)控制在1．9％之内,峰面积重复性的RSD小于4．0％,本方法可用于西孟坦对映异构体的手性分离和定量分析。     

高效毛细管电泳分离单唾液酸神经节苷脂

单唾液酸神经节苷脂在水溶液中易形成胶束，通常不被毛细管电泳分离。我们发现，使用含有α－环糊精的硼砂作为缓冲体系可以破坏胶束的形成，明显改变这些化合物的电泳行为。在最佳分离条件下，标准ＧＭ１被分裂成双峰。本文讨论了电泳缓冲液的组成及其浓度、场强、温度等参数对分离的影响。     

Calibration of polyacrylamide gel columns for the separation of oligonucleotides by capillary electrophoresis

Polyacrylamide-filled gel columns are used to separate oligonucleotide samples. For homopolymeric standard samples, plots of migration time versus molecular size are presented over a range of 30-160 bases. With 2.5-4% T and 3.3% C gels, good resolution over the examined mass range, with peak width at half height of 3 to 6 s, is obtained by applying electrical fields of 200-400 V/cm. The separation of heteropolymeric nucleotides by slab gel electrophoresis under routine conditions was compared with capillary gel electrophoresis. Using the same column and the same separation conditions, the plot of migration time versus base number is linear with an identical slope for three oligonucleotide samples which were examined, allowing a calibration of a gel-filled capillary for molecular mass determination.     

Separation and simultaneous determination of quinolone antibiotics by capillary zone electrophoresis

Summary The potential of capillary zone electrophoresis has been investigated for the separation and quantitative determination of some quinolone antibiotics. The influence of different conditions, such as the nature and concentration of the electrophoretic electrolyte, on migration time, peak symmetry, efficiency and resolution was studied. A buffer consisting of 100mm HEPES adjusted to pH 8.5 containing 10% (v/v) acetonitrile was found to furnish a very efficient and stable electrophoretic system for the separation of exoxacin, ciprofloxacin, ofloxacin, oxolinic acid, nalidixic acid and pipemedic acid. A linear relationship between concentration and peak area for each compound was obtained in the concentration range 0.25–40 μg mL⁻¹; detection limits were approximately 0.25 ng mL⁻¹. It was demonstrated that the method can be used for the simultaneous determination of these six antibiotics in serum and urine samples.     

Optimization of the separation of phenolic compounds by micellar electrokinetic capillary chromatography

A group of phenolic compounds including phenolic aldehydes, acids and flavonoids are separated by micellar electrokinetic chromatography (MECC). The influence of buffer (concentration and pH), concentration of sodium dodecylsulphate (SDS) and applied voltage were studied. To increase the selectivity of the separation and the resolution of the solutes organic solvents are added to the separation buffer, the best results were obtained when methanol was used at lower percentages. An optimized buffer (150 mM boric acid (pH 8.5)-50 mM SDS-5% methanol) provides the optimum separation with regard to resolution and migration time. This method was applied to the determination of these compounds in wine samples with good results.     

Optimization of the separation of flavonoids by micellar electrokinetic capillary chromatography: Effect of organic solvents

Summary A group of flavonoids of special interest to wine quality were separated by micellar electrokinetic chromatography (MEKC) with diode array detection. Their separation was optimized as a function of the buffer concentration and pH, the concentration of sodium dodecyl sulfate (SDS) and the applied voltage. Selectivity and resolution of the solutes were increased by adding organic solvents to the separation buffer, the best results being obtained at lower concentrations. An optimized buffer with 5% methanol provided optimum separation with regard to efficiency, resolution and migration time. The optimized method was applied to the determination of these compounds in wine samples.     

Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser-induced fluorescence detector

A capillary electrophoresis immunoassay (CEIA) was developed for the determination of trace metolcarb (MTMC) in food. The method was based on the competitive reactions between fluorescently labeled MTMC tracer and free MTMC with a limited amount of anti-MTMC antibody and the separation and determination by CE with LIF detector. A fluorescent reagent, FITC was labeled on MTMC to construct an immunofluorescent probe. CEIA experimental parameters such as the pH value and concentration of the running buffer and separation voltage as well as incubation time were systematically investigated. Under the optimized conditions, fluorescently labeled antigen and antibody bound could be well separated within 3 min using Na?B?O?/NaH?PO? buffer (20:10 mmol/L, pH 9.0) for background electrolyte, 20 kV for the separation voltage, and 20°C for the column temperature. The linear range of the method was 0.25-50.0 μg/L with LOD 0.07 μg/L. The RSD for relative migration time and relative fluorescence intensity ratio were 2.90% (intraday) and 4.73% (intraday), respectively. The proposed method has been applied to determine the residue of MTMC in food samples with the satisfactory recovery.     

毛细管电泳电导法快速检测饲料添加剂氯化胆碱

采用毛细管电泳电导法对饲料添加剂氯化胆碱进行了测定.实验优化了缓冲介质、分离电压、毛细管长度和内径等参数.结果表明:在优化条件下,氯化胆碱在4 min左右可以实现分离检测,线性范围在41.8～1.20 μg/mL,检出限为0.8 μg/mL;迁移时间和峰面积的相对标准偏差分别为0.6%、2.1%;样品加标回收率为97%～105%.将该法用于粉剂和饲料中氯化胆碱的检测,取得了满意的结果.     

Capillary zone electrophoresis for the determination of thiabendazole, prochloraz and procymidone in grapes

Capillary zone electrophoresis with UV detection was applied to the simultaneous determination of thiabendazole, prochloraz and procymidone in grapes. Electrolyte conditions such as pH, composition and concentration of the buffer, addition of organic solvent and working voltage were checked to obtain a high-performance separation of the three fungicides (by measurement of separation efficiency and resolution). The most critical parameter was the pH of the running buffer. The best separation was achieved in 4 mM phosphate solution at pH 3.5. The repeatability of the migration times, expressed as RSD, was < 0.44%. The three peaks were completely resolved with a separation efficiency up to 100,000 theoretical plates. Solid-phase extraction was used for the isolation and preconcentration of the fungicides, which provided a concentration factor of 10:1 and limits of detection lower than the maximum residue limits. The mean recoveries of the fungicides were 73.75% for thiabendazole, 41.70% for prochloraz and 92.23% for procymidone. This method was used to determine these compounds in 20 real samples taken from a local market.     

Rapid determination of globin chains in red blood cells by capillary electrophoresis using INSTCoated fused‐silica capillary

A laboratory‐made INSTCoated fused‐silica capillary has been newly used for CE separation of four mixtures of proteins in sodium phosphate BGEs at pH 3.0 and 2.5, respectively. The obtained separation efficiencies range from 145 000 theoretical plates per meter for myoglobin to 1 216 000 m^?1 for lysozyme. A total of 49–89% of the number of theoretical plates was obtained in a commercial polyvinyl alcohol coated capillary compared to the INSTCoated capillary under the same experimental conditions, 0–86% was obtained in a laboratory polyacrylamide‐coated capillary, and only 0–6% was obtained in an uncoated fused‐silica capillary. The RSD values for the intraday repeatability for an INSTCoated capillary were 0.1–1.0% (migration time) and 0.3–2.4% (peak area); RSD values for the interday repeatability in the same capillary are 0.6–1.4% (migration time) and 2.4–5.5% (peak area); RSD values for interday repeatability between different capillaries equaled 1.7–2.1% (migration time) and 2.8–10.9% (peak area). The INSTCoated capillary has been further used for rapid determination of globin chains isolated from red blood cells. A separation of α and β chains prepared from adult blood has been completed in 3 min with a peak resolution of 1.3, and the separation of α and ^Gγ chains prepared from newborn blood took 3 min with a peak resolution of 3.6.     

Separation and determination of active components in Schisandra chinensis Baill. and its medicinal preparations by non-aqueous capillary electrophoresis

A simple, economical and effective non-aqueous capillary electrophoresis separation and detection method was developed for the quantification of deoxyschizandrin and gamma-schizandrin in Schisandra chinensis Baill. and its medicinal preparations for the first time. After optimization of separation conditions, a buffer of 140 mmol/L sodium cholate in methanol was selected for separating the two analytes, but baseline separation of SA and SB in real samples was not obtained. Therefore second-order derivative electropherograms were applied for resolving overlapping peaks. Regression equations revealed good linear relationships (correlation coefficients 0.9975--0.9988) between peak heights in second-order derivative electropherograms and concentrations of the two analytes. The relative standard deviations (RSD) of the migration times and the peak height of the two constituents were in the ranges 0.62--0.79% and 0.25--2.17% (intra-day) and 1.43--2.06 and 4.08--5.72% (inter-day), respectively. The recoveries of the two constituents ranged from 93.2 to 103.0%. The results indicated that baseline separation of the analytes was sometimes hard to obtain in real samples and second-order derivative electropherograms were applicable for the resolution and analysis of overlapping peaks.     

胶束电动毛细管色谱法同时测定阿咖酚散中3种有效成分

建立了胶束电动毛细管色谱同时分离测定阿咖酚散中咖啡因、对乙酰氨基酚、阿司匹林3种有效成分的方法。对以有机碱三乙醇胺为改进剂的胆酸胶束相进行了优化,对改进剂的影响机理进行了详细讨论。最佳电泳条件如下:以40 mmol/L硼酸盐-60 mmol/L胆酸-12.5%三乙醇胺(pH 12.0)为缓冲体系,分离电压为15 kV,检测波长为254 nm。在上述条件下,14 min内实现了阿咖酚散中3组分的基线分离。咖啡因、对乙酰氨基酚和阿司匹林的线性范围分别为18.75～900.0(r=0.999 9)、2.60～62.50(r=0.992 9)、79.17～3 800 mg/L(r=0.994 0)。上述3组分迁移时间和峰高的相对标准偏差分别不高于1.8%和6.8%。咖啡因、对乙酰氨基酚和阿司匹林的检出限分别为4.6、0.17、38 mg/L。应用该法测定阿咖酚散中上述3组分,加标回收率分别为100%、100%和102%,可满足实际样品分析要求。所建立的方法简便、快速、灵敏、经济,能同时进行阿咖酚散中多种成分的分离测定。