毛细管电泳脉冲伏安电化学分离检测胺类化合物

电化学检测高效毛细管电泳自 80年代末问世以来 ,已迅速发展为一种重要的分析方法 ,但是具有许多优点的现代电分析化学方法在毛细管电泳检测中的应用还不多 .扫描伏安电化学检测是继安培检测方法之后应用较多的一种方法 ,它除具有安培检测方法的优点外 ,还能得到被测物质的电流随电压变化的伏安特性 [1～ 5 ] ,但由于在电极电位的扫描过程中会产生较大的充电电流 ,进而影响检测的灵敏度和检出限 .脉冲安培检测可获得较高的灵敏度和低的检出限 ,并减少电极的污染 ,因而被应用于高效液相色谱 [6,7] 和毛细管电泳 [8,9] 中检测有机化合物 .目前…     

毛细管电泳多道电化学检测工作站

设计的毛细管电泳多通道电化学检测系统是一个可供在同一个检测环境下，用多台电化学检测器循环对物质进行测定的工作站。工作站采用计算机控制，利用电导和伏安检测器对样品同时进行电导、氧化和还原检测，并实时对数据进行采集，处理，以图形方式显示。     

电化学分析

本文是《分析试验室》定期评述中电化学分析第六篇评述文章。它评述了从１９９７年１月至１９９８年１０月期间我国电化学分析的进展。内容分基础理论与应用研究两大部分。前者包括电化学分析理论研究、电分析化学中的化学计量学方法,后者包括极谱与伏安法,络合吸附波与催化波,线性扫描伏安法,示差脉冲伏安法,吸附溶出分析法,示波分析法,微电极、超微电极与化学修饰电极,离子选择电极与各类传感器,光谱电化学,扫描隧道显微法和液／液界面电化学分析,电化学检测／电泳、色谱技术,电化学免疫法,电位分析法及其它等。共引用文献４８３篇。     

毛细管电泳法测定市售饮料中糖类物质的研究

毛细管电泳－电化学检测技术（ＣＥ－ＥＣ）,对具有电化学活性的物质的分离检测具有极大的优越性。本文采用ＣＥ－ＥＣ技术,以铜电极为工作电极,在０．１０ｍｏｌ／Ｌ ＮａＯＨ溶液中对１０种市售饮料中的糖类物质的分离检测进行了研究。讨论了ｐＨ值,电泳操作液,分离电压,电极,工作电位等对分离检测的影响,并对１０种饮料中的糖类物质的热量进行了计算。     

单壁碳纳米管修饰的高灵敏纳米碳纤维电极

碳纳米管已被应用于电极材料,但未得到良好的电化学伏安行为;且由于碳纳米管的直径很小(几到数十纳米),制作单根的碳纳米管电极非常困难,难以实际应用.碳纳米管用于修饰电极已得到更多重视,但都在常规尺寸(毫米级)的电极上进行,这样的电极不适于在生物微环境和毛细管电泳电化学检测中应用.     

毛细管电泳安培检测扑热息痛及其水解物

研究了各种电化学预处理条件下碳纤维电极对扑热息痛及水解物的电化学行为。确定该体系最佳预处理条件为０．２Ｖ电位下阳极化１ｍｉｎ，再于－２．０Ｖ下阴极化１０ｓ。预处理后的碳纤维伏安响应得到明显提高。运用最佳条件并在支持电解中加入添加剂后，扑热息痛及其水解物在毛细管电泳上获得很好的分离和检测。其中扑热息痛的检测下限为２．７８ｐｇ；对氨基酚为１．８４ｐｇ。     

基于ZIF-8电化学传感器构建及用于检测饮料中新橙皮苷二氢查耳酮

采用电泳沉积法,成功在玻碳电极（GCE）表面制备了一层ZIF-8材料薄膜,再在其表面滴涂一层全氟化树脂溶液（Nafion）,形成ZIF-8/Nafion复合膜,用于构建检测高倍甜味剂新橙皮苷二氢查耳酮（NHDC）的电化学传感器。利用电化学交流阻抗（EIS）技术对该传感器进行表征,采用循环伏安法（CV）研究NHDC在ZIF-8/Nafion电极表面的电化学行为,并优化实验条件。NHDC在ZIF-8/Nafion膜上有灵敏的响应。采用差分脉冲伏安法（DPV）建立了定量检测NHDC的方法,方法线性范围为0.16～160μmol/L,检出限为56 nmol/L。该方法检测饮料中NHDC的加标回收率范围为99.0%～101.3%。     

计算机化的数字交流伏安法

电化学交流阻抗技术在电化学理论研究和测量上是十分有用的方法。Smith等人讨论了计算机辅助的交流极谱方法中许多人们感兴趣的问题,并曾使用快速富里叶变换技术同时检测多种谐波成分。近来,Bond进行了微处理器辅助的数字交流极谱仪的研究。迄今,计算机化的交流伏安仪方面的研究国内尚未见报道。本文在前文多功能仪器系统的基础上进一步建立了阶梯扫描交流伏安法并应用于实验研究,获得了满意的结果。     

循环伏安和现场红外光谱电化学研究镉(Ⅱ)在普鲁士蓝/铂修饰电极上的反应

报道了普鲁士蓝(PB)膜修饰Pt电极在CdCl_2溶液中进行循环伏安(CV)扫描,衍生为含有部分六氰亚铁酸镉(CdHCF)混合修饰膜的电化学反应,并对其反应机理进行了电化学和现场红外光谱电化学(FTIRs)的研究.实验结果表明,这一混合膜中PB和CdHCF两种成分之间的相互影响并不大,两种物质基本上保持了各自为纯物质时的电化学特性.     

Nafion修饰铂电极电化学还原法测定溶液中的一氧化氮

采用电化学还原法对溶液中一氧化氮（ＮＯ）进行测定，研究对比了电化学氧化和电化学还原对ＮＯ检测的选择性和灵敏度，同时研究了工作电极表面修饰膜厚度、工作电极在被测溶液中的吸附时间，扫描速度对峰电流及峰电位的影响，证明电化学还原法选择性好，方法检出限为６μｍｏｌ／Ｌ，线性范围１０￣８００μｍｏｌ／Ｌ。     

Capillary Zone Electrophoresis of Eleven Priority Phenols with Amperometric Detection

A scheme for separation and detection of eleven priority phenols using capillary zone electrophoresis (CZE) coupled with amperometric detection is described. With a capillary of I.D. 50 μm and length 62.5 cm at 9 kV and an electrophoretic buffer of 20 mM CHES (pH 10.1), complete separation of the eleven compounds was achieved in less than 17 min. Amperometric detection was carried out using a carbon fiber microelectrode of diameter 9 μm inserted into the end of the detection capillary. Linearity over two orders of magnitude was generally obtained for the eleven priority phenols. With an electrode potential+1.10 V (vs. Ag/AgCl reference), the concentration limits of detection were in the sub-ppm (10^?6 M) level. This method was successfully applied to analysis of priority phenols in industrial waste water.     

毛细管电泳微机化扫描伏安检测器

描述了一种毛细管电泳微机化扫描伏安检测器,用微机通过D/A和A/D转换器控制扫描电压和采集电流信号,用12bit的D/A转换器和12bit的A/D转换器通过伏安仪分别与Ag/AgCl参比电极和工作电极相连,进行电位控制和数据采集.讨论了扫描电位的产生和数据采集的控制方法,并用本系统分离测定了对苯二酚和儿茶酚,结果令人满意.     

毛细管电泳安培法检测酚类化合物

使用自行设计组装的毛细管电泳柱端安培检测系统 ,对四个酚类化合物进行了分离检测。研究了工作电极、缓冲液及其 p H值、检测电压和分离电压对分离检测的影响。在优化条件下 ,4个酚在 5× 1 0 -6～ 5× 1 0 -4 mol/L范围内峰高与浓度成良好的线性关系 ,检测下限为 8.5× 1 0 -7mol/L     

Determination of homotaurine as impurity in calcium acamprosate by capillary zone electrophoresis.

A method is reported which allows the quantification of homotaurine as an impurity in the drug. After addition of taurine as an internal standard, the sample is derivatised with fluorescamine at ambient temperature in 10 mM borate buffer, pH 9.2. The analytes are separated by capillary zone electrophoresis in a 31.2 cm (21 cm to the detector) x 100 microns I.D. fused-silica capillary at a potential of +7 kV and 25 degrees C. A 40 mM borate buffer, pH 9.2, is used as the electrolyte and detection is carried out at 205 nm. The validation tests showed that the method is reliable between 0.01% and 0.15% (m/m) of homotaurine with respect to the active drug. The limits of quantitation (0.01%, m/m) and detection (0.004%, m/m) allows to control the homotaurine content of the drug substance for which the maximum tolerated level is 0.05% (m/m). The proposed procedure (derivatisation and separation) developed in CE is rapid (20-25 min) by comparison to that currently used in HPLC (75 min). Satisfactory agreement was found between several batches of acamprosate analysed by CE and HPLC.     

Capillary electrophoresis method for fexofenadine hydrochloride in capsules

A simple, accurate, and effective capillary electrophoresis method with ultraviolet absorbance detection was developed and validated for the quantitation of the antihistamine fexofenadine in capsules. The separation was performed with an uncoated fused-silica capillary (47 cm x 75 microm id) and was operated at 20 kV potential. Temperature was maintained at 25 degrees C. The run buffer was prepared with 20mM Na2B4O7 x 10 H2O. Software was used for system control, data acquisition, and analysis. Method validation was performed by evaluation of the analytical parameters linearity, precision, accuracy, limits of detection and quantitation, and specificity. The method was linear (r = 0.9999) at concentrations ranging from 20 to 100 microg/mL, precise (relative standard deviation intra-assay = 1.2, 1.6, and 1.8% and interassay = 1.5%); accurate (recovery = 98.1%); and specific. The limits of detection and quantitation were 0.69 and 2.09 microg/mL, respectively. The method was compared to the liquid chromatography method developed previously by the authors for the same drug, and no significant difference was found between the 2 methods in fexofenadine hydrochloride quantitation.     

Microscale determination of purines in tissue samples by capillary liquid chromatography with electrochemical detection

A microscale method for purines involved in intracellular signaling and energy metabolism, including ADP, ATP, cyclic-AMP, NADH and GTP, was developed. The analytes were separated on a fused-silica capillary liquid chromatography column (50 microm inner diameter by 25 cm long) packed with 7 microm reversed-phase particles and detected with a carbon fiber cylinder microelectrode at +1.50 V versus Ag/AgCl reference electrode. With an acetonitrile gradient, the separation was carried out within 15 min. With a 100 nl injection volume, the detection limits varied from 0.9 to 8 fmol depending upon the analyte. The low detection limits make the method suitable for analysis of small tissue samples. As a demonstration of the method, islets of Langerhans were analyzed for their adenosine-related messenger content.     

Capillary electrophoresis-amperometric determination of antioxidant propyl gallate and butylated hydroxyanisole in foods.

Capillary electrophoretic separation coupled with end-column amperometric detection for the simultaneous quantification of butylated hydroxyanisole (BHA) and propyl gallate (PG) in food was developed. Important factors affecting separation and detection, such as the running buffer, separation voltage, and detection potential, were investigated in detail. An improved working electrode preparation method was used, where a carbon disk of 33 microm in diameter was sealed in a tip and positioned opposite the outlet of a capillary. The experiments indicated that the preparation method was simple, and the obtained electrode exhibited good flexibility and stability for the determination of phenolic antioxidants. The separation was carried out within 5 min using a 50 cm length capillary, with a solution containing 5 mM phosphate and 5 mM borax of pH 8.84 as a separation buffer, and a separation potential of 20 kV. Amperometric detection was achieved with an applied potential of 0.70 V versus Ag|AgCl| saturated KCl. There was excellent linearity between the peak current and the concentrations of the analytes in the range of 1.8 - 180.2 microg/mL for BHA and 10.6 - 212.2 microg/mL for PG, respectively. Relative standard deviations of 4.92% for BHA and 5.27% for PG were obtained, respectively. The developed method was successfully applied for the determination of antioxidants in several commercial foods.     

毛细管电泳/非接触式电导法分离检测手性药物氨氯地平对映体

采用毛细管电泳/电容耦合非接触式电导( CE/C4 D),以18 mmol/L柠檬酸+6 mmol/L氨水+12 mg/L羟丙基甲基纤维素(HPMC)+ 35 mmol/L羟丙基-β-环糊精(HP-β-CD)为电泳运行液,熔融石英毛细管(50μm i.d.×45 cm,leff=40 cm),正高压(+15 kV)分离...     

Reversed-phase capillary electrochromatography for the simultaneous determination of acetylsalicylic acid, paracetamol, and caffeine in analgesic tablets

The separation and simultaneous determination of caffeine, paracetamol, and acetylsalicylic acid in two analgesic tablet formulations was investigated by capillary electrochromatography (CEC). The effect of mobile phase composition on the separation and peak efficiency of the three analytes was studied and evaluated; in particular, the influence of buffer type, buffer pH, and acetonitrile content of the mobile phase was investigated. The analyses were carried out under optimized separation conditions, using a full-packed silica capillary (75 microm ID; 30.0 cm and 21.5 cm total and effective lengths, respectively) with a 5 microm C8 stationary phase. A mixture of 25 mM ammonium formate at pH 3.0 and acetonitrile (30:70 v/v) was used as the mobile phase. UV detection was at 210 nm. Good linearity was found in the range of 50-200, 20-160, and 4-20 microg/mL for acetylsalicylic acid (r2=0.9988), paracetamol (r2=0.9990) and caffeine (r2=0.9990), respectively. Intermediate precision (RSD interday) as low as 0.1-0.8% was found for retention times, while the RSD values for the peak area ratios (Aanalyte/AIS) were in the range of 1.9-2.9%. The optimized CEC method was applied to the analysis of the studied compounds present in commercial tablets.