苏丹红Ⅰ号的毛细管电泳安培检测

建立了毛细管电泳安培法测定苏丹红Ⅰ号的方法.考察了缓冲液种类、浓度和pH值,分离电压、进样时间、检测电位等因素对分离检测的影响.以10 mmol/L硼砂盐(pH 9.3)为缓冲液,检测电位1.05 V(vs.SCE),分离电压21 kV,电动进样(12 kV)8 s,苏丹红Ⅰ号在1.13×10-9～1.13×10-7mol/L范围内,浓度与峰面积具有良好的线性关系,回收率为93.5%～102.7 %,检测限为1.13×10-9 mol/L.该方法成功应用于辣椒粉样品的检测,结果令人满意.     

Determination of carbohydrates by capillary zone electrophoresis with amperometric detection at a nano-nickel oxide modified carbon paste electrode

In this paper, a nano-NiO modified carbon paste electrode in capillary zone electrophoresis with amperometric detection (CZE-AD) was firstly applied to the determination of carbohydrates. Effects of several important factors such as detection potential, the concentration of running buffer, separation voltage and injection time were investigated to acquire the optimum conditions. Under the selected optimum conditions, three carbohydrates: glucose, sucrose and fructose could be perfectly separated within 20 min. The relationships between peak current and concentration of three carbohydrates were linear over about 3 orders of magnitude with detection limits (S/N = 3) ranging from 3.0 × 10⁻⁷ to 6.0 × 10⁻⁷ mol L⁻¹. The electrode was stable, and can be used for at least one week. The proposed method has been successfully applied to monitor carbohydrates in the real samples with satisfactory assay results.     

Study on extraction efficiency of natural antioxidant in coffee by capillary electrophoresis with amperometric detection

Capillary electrophoresis with amperometric detection (CE-AD) has been used for the determination of catechin, rutin, ferulic acid, o-dihydroxybenzene, chlorogenic acid, caffeic acid, gallic acid, and protocatechuic acid in coffee. Comparison of extraction efficiency of antioxidants using different polar solvents was also conducted by this method. Effects of several important factors including the acidity and concentration of running buffer, separation voltage, and working electrode potential, were evaluated to obtain the optimum analysis conditions. The working electrode was a 300 um carbon disc electrode at an applied potential of +0.95 V (vs. saturated calomel reference electrode). Under the optimum conditions, the analytes can be well separated within 26 min in a 75 cm length fused-silica capillary (i.d. 2.5 × 10⁻⁵ m). The current response was linear over three orders of magnitude with detection limits (S/N = 3) ranging from 6.0 × 10⁻⁸ to 3.6 × 10⁻⁷ g/mL for all analytes.     

Simple determination of main organic acids in grape juice and wine by using capillary zone electrophoresis with direct UV detection

An accurate, simple and rapid capillary zone electrophoresis (CZE) method with direct UV detection has been set up for the determination of main organic acids in grape juice and wine. The determination of tartaric, malic, and citric acids in grape juices and tartaric, malic, succinic, acetic, lactic and citric acids in wines can be achieved in less than 3 min with only a simple dilution and filtration treatment of the sample. Validation parameters of the method as detection and quantification limits, linearity, precision (intraday and interday analysis) and recovery were also studied in grape juice, white wine, rose wine and red wine, separately. The proposed method decreases the analysis times of the previous reported CZE methods and allows the rapid control of the grape maturity, the winemaking processes and the detection of wine alterations and/or illnesses.     

毛细管区带电泳非衍生化直接测定蜂蜜中糖含量

建立了一种新的测定蜂蜜中糖含量的方法,并探讨了检测机理。以弹性石英毛细管柱（有效长度/总长度=52/62 cm）为分离柱,130 mmol/L的Na OH+30 mmol/L的Na2HPO4溶液（p H=12.8）为运行缓冲液,温度20℃,分离电压在1 min内升至16 k V,测定波长为270 nm,以20 psi的压力进样,内标峰面积法计算含量。经测定:蜂蜜样品中果糖、葡萄糖、蔗糖和麦芽糖含量分别为42.8%、36.1%、4.67%和2.16%,检测机理可能是糖在强碱溶液中发生光化学反应,检测在非平衡态进行;果糖、葡萄糖在0.04⁰.8 mg/m L,蔗糖、麦芽糖在0.005⁰.1 mg/m L范围内线性关系良好;最低检测限果糖和葡萄糖为9μg/m L,蔗糖和麦芽糖为18μg/m L,明显低于高效液相色谱示差检测法;果糖、葡萄糖、蔗糖、麦芽糖回收率分别为99.4%、97.9%、97.1%、102.7%,方法回收率良好。此方法准确、简便,可用于蜂蜜中糖的测定。      

Rapid determination of sodium in milk and milk products by capillary zone electrophoresis

A capillary zone electrophoresis method for the determination of Na in milk and milk products was developed and compared with an International Organization for Standardization/International Dairy Federation standard method that is based on flame atomic absorption spectrometry. The adoption of a background electrolyte consisting of 10 mM imidazole adjusted to pH 3.75 by the addition of oxalic acid allowed baseline separation of Na from other milk cations and from Li ion, which was adopted as an internal standard. Method validation was performed and the results for linearity, precision, limit of detection, limit of quantification, and recovery are presented. The procedure was tested on commercial milk samples differing in fat content (whole, semiskimmed, and skimmed) and processing conditions (pasteurization, UHT sterilization, and microfiltration). The reliability of the method was confirmed for different varieties of cheese and other milk products. The method enables the routine measurement of Na content by a rapid and accurate capillary zone electrophoresis procedure.     

Determination of levoglucosan from smoke samples using microchip capillary electrophoresis with pulsed amperometric detection

Separation and detection of native anhydrous carbohydrates derived from the combustion of biomass using an electrophoretic microchip with pulsed amperometric detection (PAD) is described. Levoglucosan represents the largest single component of the water extractable organics in smoke particles and can be used to trace forest fires or discriminate urban air pollution sources. Detection of levoglucosan and other sugar anhydrides in both source and ambient aerosol samples is typically performed by gas chromatographic (GC) separation with mass spectrometric (MS) detection. This method is cost, time, and labor intensive, typically involving a multistep solvent extraction, chemical derivatization, and finally analysis by GC/MS. However, it provides a rich wealth of chemical information as the result of the combination of a separation method and MS and exhibits good sensitivity. In contrast, microchip capillary electrophoresis offers the possibility of performing simpler, less expensive, and faster analysis. In addition, integrated devices can be fabricated and incorporated with an aerosol collection system to perform semicontinuous, onsite analysis. In the present report, the effect of the separation potential, buffer pH and composition, injection time, and pulsed amperometric detection parameters were studied in an effort to optimize both the separation and detection of anhydrous sugars. Using the optimized conditions, the analysis can be performed in less than a minute, with detection limits ranging from 22 fmol (16.7 microM) for levoglucosan to 336 fmol (258.7 microM) for galactosan. To demonstrate the capabilities of the device, a comparison was made between GC/MS and microchip electrophoresis using an aerosol source sample generated in a wood-burning chamber. A second example utilizing an ambient aerosol sample illustrates a matrix interference necessitating additional method development for application to samples not dominated by wood smoke.     

高效毛细管电泳-紫外检测法分离测定氨基酸的含量

利用高效毛细管区带电泳直接紫外检测法对8种非衍生化氨基酸进行了分离分析条件的研究,采用重力进样,进样高度20cm,进样时间30s,弹性石英毛细管内径75μm,有效分离长度48cm,分离电压-20kv,在浓度为50mmol/L,pH10的硼砂缓冲溶液中加入0.5mmol/L的十六烷基三甲基溴化铵作为电渗流改性剂,在4min内,8种氨基酸得到了有效分离。各氨基酸的线性范围为5～150μg/mL或1～80μg/mL,检出限在0.5～2μg/mL之间。应用于由糖蜜生产亮氨酸的发酵液中缬氨酸和亮氨酸含量的测定,结果满意。     

Simultaneous analysis of acidulants and preservatives in food samples by using capillary zone electrophoresis with indirect UV detection

Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of acidulants and preservatives in food samples. When a solution of tris (hydroxymethyl) aminomethane, trimellitic acid and poly (vinyl alcohol) was used as the background electrolyte, the nine acidulants and four preservatives listed in the Japanese Food Sanitation Law were detected within 8 min. The calibration curves plotted from the peak height of each analyte were linear with a correlation coefficient of 0.99. The relative standard deviations (n = 10) of the peak height ranged from 1.2% to 4.7%. The detection limits for these species ranged from 0.6 to 5.3 mg/L at a signal-to-noise ratio of three. The method developed method was applied to the simultaneous analysis of acidulants and preservatives in a wide variety of food samples.     

A rapid quantitative determination of phenolic acids in Brassica oleracea by capillary zone electrophoresis

A simple and rapid capillary zone electrophoresis method to quantitatively determine the phenolic acid contents in brassica vegetables is described. Phenolic compounds were extracted from broccoli, broccolini, Brussels sprouts, cabbage and cauliflower and the main hydroxycinnamic acids (sinapic, ferulic, p-coumaric and caffeic acids) were isolated by solid phase extraction with C18 cartridges. Using an optimised method, the four analytes were separated in less than 7 min in a 50 μm × 60 cm capillary with a 15 mM borate buffer (pH = 9.13) and a separation voltage of 30 kV at 30 °C. A linear relationship was observed for the method (r = 0.9997–0.9999) with detection limits ranging from 1.1 to 2.3 mg/kg of vegetables for the analytes. This method demonstrated good reproducibility with coefficients of variation of less than 5% for peak area and less than 1% for migration time (n = 7). The method was successfully applied to quantitatively determine the phenolic acid contents in a range of brassica vegetables and the results were in good agreement when compared to those from high performance liquid chromatography analysis.     

毛细管电泳安培检测法快速测定巧克力中的香兰素

运用毛细管电泳安培检测法研究了巧克力中香兰素的快速测定方法,研究了电极电位、缓冲液的浓度和pH、分离电压以及进样时间等因素对分离测定的影响。在30mmol/L的硼砂（pH9.24）运行缓冲液中,施加15kV的分离电压及+0.65V（vs.SCE）的电极电位条件下,铜电极对香兰素有很好的响应。香兰素在5.0×10-6～1.0×10-3g/mL范围内存在较好的线形关系,检测限为3.87×10-7g/mL（S/N=3）。对实际样品的测定,回收率为96.5%～102.8%,结果令人满意。      

离子色谱-脉冲安培检测法测定酱油中的糖

以氢氧化钠为淋洗液,在CarboPac PA10高容量阴离子交换柱上分离,脉冲安培检测了几种常见类型酱油中阿拉伯糖、半乳糖、葡萄糖、木糖、果糖及蔗糖,其检出限(25μL进样,S/N=3)为2～8 μg·L-1.这六种糖均具有较宽的线性范围(0.02～30 mg·L-1),酱油测定结果的相对标准偏差在0.11%～4.10%之间,六种糖类的加标回收率在94.1%～103.8%之间.该方法检测糖具有简便快捷、分离效果好、无需衍生、灵敏度高等优势,适用于各种酱油中糖组分的分析.     

Feasibility of using capillary zone electrophoresis with photometric detection for the trace level detection of bromate in drinking water

The feasibility of applying a capillary zone electrophoretic (CZE) method for the trace analysis of bromate, a suspect human carcinogen, in drinking water was studied. Using a bare fused-silica capillary (75 µm inner diameter) coupled with indirect ultraviolet detection (200 nm), 0.25 mM cetyltrimethylammonium bromide, 5% methanol and 5.0 mM phthalate at pH 5.0–5.2, an electrokinetic injection of 15 kV and 10 s, a separation voltage of 18 kV (negative polarity) and a capillary temperature of 15°C, bromate was detected in high purity water at ≤10 µg l^?1. The method was applied to three bottled water sources and to local municipal water. If needed, additional sample-handling steps, consisting of an off-line pre-concentration step and pH adjustment to 5.5, was used to improve detection limits (from a high of 400 µg l^?1 to ≤10 µg l^?1) and baseline noise. Signal-to-noise ratios also increased by adding sodium phosphate (1.1 µg ml^?1) to all sources prior to analysis. Although the CZE method was capable of detecting bromate at levels ≤10 µg l^?1 with an analysis time of 8–9 min, high variability (>10% relative standard deviation) precluded its application to some of sources without further method development. Nonetheless, this method could serve as the basis for the detection of bromate to specific water sources with minimal or no optimization     

毛细管电泳法同时检测南蛇藤中三种黄酮类活性成分

目的:建立同时测定南蛇藤中芦丁、山奈酚及槲皮素含量的毛细管电泳法,分析结果差异,探讨南蛇藤的药用质量控制方法。方法:采用30mmol·L-1硼酸钠缓冲液（pH=9.0）,20kV分离电压,254nm波长条件下采用毛细管电泳法测定芦丁、山萘酚、槲皮素含量。结果:黄酮类物质芦丁、山萘酚和槲皮素的对照品在12min内实现完全分离,在2.5⁴00μg·mL-1范围内呈良好的线性关系。结论:南蛇藤中黄酮类物质含量丰富,毛细管电泳技术可以同时测定南蛇藤中芦丁、山奈酚与槲皮素,具有较好的准确度和精密性,为临床和科研提供了一种简单快速的检测方法,为南蛇藤的药用质量控制提供了技术方法和理论数据。      

毛细管电泳法同时检测南蛇藤中三种黄酮类活性成分

目的:建立同时测定南蛇藤中芦丁、山奈酚及槲皮素含量的毛细管电泳法,分析结果差异,探讨南蛇藤的药用质量控制方法.方法:采用30mmol·L-1硼酸钠缓冲液(pH=9.0),20kV分离电压,254nm波长条件下采用毛细管电泳法测定芦丁、山萘酚、槲皮素含量.结果:黄酮类物质芦丁、山萘酚和槲皮素的对照品在12min内实现完全分离,在2.5～400μg· mL-1范围内呈良好的线性关系结论:南蛇藤中黄酮类物质含量丰富,毛细管电泳技术可以同时测定南蛇藤中芦丁、山奈酚与槲皮素,具有较好的准确度和精密性,为临床和科研提供了一种简单快速的检测方法,为南蛇藤的药用质量控制提供了技术方法和理论数据.     

Determination of major metal cations in milk by capillary zone electrophoresis

A reliable and rapid capillary zone electrophoresis method for the determination of the major of cations in milk samples was developed. Sample preparation consisted of dilution, acidification to pH 4.0 with 1 mol L⁻¹ acetic acid and filtration. The complete separation of K⁺, Ca²⁺, Na⁺ and Mg²⁺ could be achieved in 4 min with a simple electrolyte composed of 10 mmol L⁻¹ imidazole and 1 mol L⁻¹ acetic acid (pH 3.6). The running voltage was 25 kV at 25 °C. Indirect UV detection was achieved at 185 nm. Detection limits ranged from 0.06 to 0.57 mg L⁻¹ and quantification limits ranged from 0.16 to 0.62 mg L⁻¹. Precision data showed relative standard deviations (RSD%) lower than 4.1% for relative migration time and 2.4% for milk concentrations, respectively. Recoveries of cations in samples analysed ranged from 97.7% to 101.1%. Thirty samples of milk were analysed, obtaining mean values of 1.46, 1.19, 0.505 and 0.126 g L⁻¹ for K⁺, Ca²⁺, Na⁺ and Mg²⁺, respectively.     

Direct determination of free tryptophan contents in soy sauces and its application as an index of soy sauce adulteration

A simple and rapid HPLC method using UV detector for determination of tryptophan (Trp) contents in pure fermented soy sauces, acid-HVP, and commercial soy sauces was developed. The method requires only simple sample pretreatment. The limit of detection (LOD) is estimated at 1 mg/L (signal-to-noise ratio of 3), and the recovery yields ranged from 92% to 108%. The analysis showed that Trp in all of the analysed acid-HVP samples was not detected and there was obvious detection of Trp (ranged from 136.4 to 261.8 mg/L) in all of the analysed fermented soy sauce samples. The observations suggest that Trp is a practical index of pure fermented soy sauce. The absence of Trp contents or lower level of Trp contents than that in pure fermented soy sauces suggests the soy sauces are not pure fermented soy sauces or presence of soy sauce adulteration. Simultaneous determination of levulinic acid (LV) in samples may be a good help in making assessment of soy sauce adulteration with acid-HVP.     

Rapid determination of gizzerosine in fish meals using microchip capillary electrophoresis with laser-induced fluorescence detection

ABSTRACT

Sensitive detection of gizzerosine, a causative agent for deadly gizzard erosion in chicken feeds, is very important to the poultry industry. In this work, a new method was developed based on microchip capillary electrophoresis (MCE) with laser-induced fluorescence (LIF) detection for rapid analysis of gizzerosine, a biogenic amine in fish meals. The MCE separation was performed on a glass microchip using sodium dodecyl sulfate (SDS) as dynamic coating modifier. Separation conditions, including running buffer pH and concentration, SDS concentration, and the separation voltage were investigated to achieve fast and sensitive quantification of gizzerosine. The assay proposed was very quick and could be completed within 65 s. A linear calibration curve was obtained in the range from 0.04 to 1.8 μg ml^–1 gizzerosine. The detection limit was 0.025 μg ml^–1 (0.025 mg kg^–1), which was far more sensitive than those previously reported. Gizzerosine was well separated from other endogenous components in fish meal samples. Recovery of gizzerosine from this sample matrix (n = 3) was determined to be 97.2–102.8%. The results from analysing fish meal samples indicated that the present MCE-LIF method might hold the potential for rapid detection of gizzerosine in poultry feeds.     

高效液相色谱法检测酱油中羟脯氨酸的含量

实验建立了柱前衍生高效液相色谱分析酱油中羟脯氨酸(hydroxyproline,Hyp)含量的方法。样品经乙醇提取,以2,4-二硝基氟苯为衍生试剂,采用GeminiC18(4.6×250mm,5μm)色谱柱分离,检测波长为360nm。Hyp质量浓度与其峰面积在10～320mg/L范围内具有良好的线性关系,相关系数为0.9992。回收率为97.19%～110.18%,检出限为2.5mg/L。对实际样品中相对Hyp含量(表示为每克氨态氮中所含羟脯氨酸的毫克数)进行检测发现,纯酿造酱油在0.67～1.93mg/g之间,酸水解植物蛋白液在9.51～20.11mg/g之间,酸水解猪皮和猪肌肉分别为855.55,37.03mg/g,三类样品间存在较明显的差异。上述结果提示,Hyp并非胶原蛋白中所特有,但通过检测酱油样品中Hyp含量有可能区分酱油中是否添加酸水解蛋白液。     

一种利用毛细管电泳间接测定生鲜乳中添加大豆分离蛋白的方法

运用高效区带毛细管电泳法以pH2.7浓度配制为15mmol/L柠檬酸-20mmol/L柠檬酸三钠作电泳缓冲液同时测定了生鲜乳蛋白和大豆分离蛋白。结果显示β-CN峰面积和迁移时间的相对标准偏差(RSD)分别为3.01%和0.62%,κ-CN峰面积和迁移时间的RSD分别为2.03%和0.49%,大豆分离蛋白峰面积和迁移时间的RSD分别小于5.12%和0.48%,均满足定性和定量分析的要求。建立了利用蛋白峰面积比例关系间接测定生鲜乳中大豆分离蛋白的分析方法,其中β-CN和κ-CN检测限分别为0.17mg/L和0.23mg/L,回收率为99.37%和99.23%,大豆分离蛋白检测限和回收率分别为5.73mg/L和87.44%.