Determination of Roxithromycin Tablets by Capillary Electrophoresis Employing Non-aqueous Media with Square-wave Amperometric Detection

A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.

Study on Rhizoma Chuanxiong based on capillary electrophoresis with amperometric detection

A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum condit...

Studies of Active Ingredients in Cough Syrup by Capillary Zone Electrophoresis with Amperometric Detection

The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0 9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.

Amperometric Detection of Histamine and Amino Acid Neurotransmitters in Capillary Electrophoresis with Copper Microelectrodes

Copper microelectrodes were used in microvoltammetry to detect histamine and several amino acid neurotransmitters. High sensitivity was obtained through the use of copper microelectrodes, and detection limits of 50 nmol/L and 90 nmol/L were obtained for histamine and histidine, respectively. Furthermore, histamine and several amino acids neurotransmitters were firstly separated and detected by capillary electrophoresis with amperometric detection on copper microelectrodes. Mass limits of 490 amol and 440 amol were achieved for histamine and histidine, respectively, by using this mothod.

Detection of Catecholic Compounds with Field-ampilfied CZE-Amperometry

On-column sample stacking technique has been used extensively in capillary zone electrophoresis (CZE) to enhance the sensitivity of the measurements with UV-Vis detection. However, the detection limits for CZE-separation are still limit- ed due to the poor sensitivity of a UV-Vis detector. We incorporated field-amplified sample stacking technique into CZE with amperometric detection. Compared with the conventional electromigration injection , a negative peak of water was observed and a great enhancement of signals was obtained. The results in phosphate buffer with sodium dodecyl sulfate (SDS ) and 2-N-(morpholino) ethane sulphonic acid ( MES ) buffer were compared. Subnanomolar concentration limits for cate- cholamine neurotransmitters (dopamine, norepinephrine , epinephriine) and isopro- terenol were achieved in the 25 um capillary with two or three orders of magnitude lower than those with amperometric detection reported previously.

Determination of isoniazid and hydrazine by capillary electrophoresis with amperometric detection at a Pt-particle modified carbon fiber microelectrode

Capillary electrophoresis (CE)/electrochemical detection (EC) for the simultaneous determination of hydrazine and isoniazid has been developed. The electrochemical method uses a novel modified electrode dispersed with ultrafine platinum particles on the surface of a 30 mu m carbon fiber microelectrode. The unique characteristic of the Pt-particles modified carbon fiber microelectrode is its excellent stability. The current measurement for hydrazine is more sensitive than that of isoniazid. Selective determination of trace amount of free hydrazine in isoniazid and its formulation can be achieved at applied potential of 0.5 V.

Utilization of a platinum-modified carbon fiber electrode in capillary electrophoresis with amperometric detection

High performance capillary electrophoresis (HPCE) is a powerful tool for separation of complex compounds. Capillary electrophoresis with amperometric detection is a prospective research area in HPCE and has attracted wide attention because of its high sensitivity, small dead volume and inexpensive equipment. Only a few reports on the use of chemically modified electrode (CME) in capillary electrophoresis have been published. In this note a novel modified electrode dispersed with ultrafine platinum particles on the surface of a 30 7μm carbon fibre microelectrode

Fast Determination of Ethylendiamine in Aminophylline Tablets by Small-sized Capillary Electrophoresis with Amperometric Detection

A novel method for fast determination of ethylendiamine （EDA） in Aminophylline Tablets has been developed by small-sized capillary electrophoresis with amperometric detection （small-CE-AD） coupled with field-amplified sample injection （FASI）. Under the optimum conditions, EDA and four aliphatic diamine homologs （1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane and 1,6-diaminohexane） could be well separated within 6 min at a separation voltage of 2.0 kV in an acetate buffer solution of pH 3.8 with low limit of detection （LOD） of 1.3 × 10^-11 g/mL for EDA （S/N=3）. The proposed method has been successfully applied to direct deter- mination of EDA content in different batches of Aminophylline Tablets. The method does not require off-line preconcentration and derivatization steps, which should find wide application fields including pharmaceuticals as an alternative to conventional and microchip CE approaches.

Determination of Four Active Ingredients in Vc Yinqiao Tablets by Capillary Zone Electrophoresis with Amperometric Detection

A simple, reliable and reproducible method, based on capillary zone electrophoresis with amperometric detection （CZE-AD）, has been developed for simultaneous determination of four active ingredients in Vc Yinqiao tablets including paracetamol, vitamin C, caffeic acid and chlorogenic acid. A carbon-disk electrode was used as working electrode and 0.95 V （versus SCE） was selected as detection potential. The optimal conditions of CZE experiment were 30 mmol·L^-1 borate solution （pH 9.5） as running buffer, 14 kV as separation voltage and 8 s （14 kV） as electro-kinetic sampling time. Under the selected optimum conditions, paracetamol, vitamin C, caffeic acid and chlorogenic acid could be perfectly separated within 22 min, and their detection limits （S/N=3） ranged from 5×10^-7 to 1 ×10^-6 mol·L^-1. This proposed method demonstrated good reproducibility with relative standard deviations of less than 3% for both migration time and peak current （n=7）. The utility of this method was demonstrated by monitoring a kind of compound medicine named Vc Yinqiao tablets and the assay results were satisfactory.

Simultaneous Determination of Catecholamines and Related Metabolites by Capillary Electrophoresis with Amperometric Detection

An electrophoretic method was developed for the determination of several important catecholamine markers, namely norepinephrine, epinephrine, dopamine, metanephrine, vanillylmandelic acid and homovanillic acid in urine samples. Under the optimum conditions, the six marker compounds could be well separated with the major coexisting interference compound uric acid within 24 rain at a separation voltage of 16 kV in a borate running buffer （80 mmol/L, pH=9.48）. Highly linear response can be obtained over three orders of magnitude for the above markers with the low limits of detection ranging from 1.0 ng/mL to 5.0 ng/mL（S/N=3）. The proposed capillary electrophoresis with amperometric detection（CE-AD） method has been used to simultaneously determine the six catecholamine markers in urine samples of healthy volunteers and patients suffering from different diseases avoiding redundant measurements and high assay cost; and the electrochemical profiles can suggest more diagnostic information of multiple diseases, which provides a promising and convenient entry into primary diagnoses of several clinical diseases.

Fast Determination of Clenbuterol and Salbutamol in Feed and Meat Products Based on Miniaturized Capillary Electrophoresis with Amperometric Detection

The fast separation capability of a novel miniaturized capillary electrophoresis with an amperometric detection （μCE-AD） system was demonstrated by determining clenbuterol and salbutamol in real samples. The effects of several factors such as the acidity and concentration of the running buffer, the separation voltage, the applied potential and the injection time on CE-AD were examined and optimized. Under the optimum conditions, the two β-agonists could be baseline separated within 60 s at a separation voltage of 2 kV in a 90 mmol/L H3BO3-Na2B4O7 running buffer （pH 7.4）, which was not interfered by ascorbic acid and uric acid. Highly linear response was obtained for above compounds over three orders of magnitude with detection limits ranging from 1.20×10^-7 to 6.50×10^-8 mol/L （S/N=3）. This method was successfully used in the analysis of feed and meat products with relatively simple extraction procedures.

Capillary Zone Electrophoresis with Amperometric Detection for Composition Analysis of Laminarin

The composition of laminarin was firstly determined by analyzing its hydrolysis monosaccharides with capillary zone electrophoresis-amperometric detection (CZE-AD). Under the selected optimum conditions, fucose, galactose, glucose, mannose and xylose, which are hydrolysis products of laminarin, could be perfectly separated within 20 min and showed significant current responses at copper electrodes. The linear ranges of fucose, galactose and glucose were from 1.0×10 -6 to 2.0×10 -4 mol·L -1, those of mannose and xylose were from 5.0×10 -6 to 2.0×10 -4 mol·L -1, and their detection limits were at 10 -7 mol·L -1 level (S/N=3). The molar ratio of fucose, galactose, glucose, mannose and xylose in laminarin was 10.5∶2.8∶1.0∶7.3∶3.4 and the purity of this polysaccharide leached by the introduced leaching method was 95.7%. Compared to usual UV-vis and other spectrometric methods, analyzing polysaccharide by this method has some merits of quickness, low-volume sampling, simple instrumentation, high sensitivity and high reproducibility.

烟草中糖类物质的高效毛细管电泳-安培检测研究

将高效毛细管电泳－安培检测技术（ＨＰＣＥ－ＡＤ）用于不同烟草样品中糖类物质的测定。在 １×１０－６ｍｏｌ／Ｌ～１×１０－３ ｍｏｌ／Ｌ范围内，存在良好的线性关系，葡萄糖、果糖、蔗糖和麦牙糖的检测限均小于 ５．０ ×１０－７ｍｏｌ／Ｌ，结果令人满意。

毛细管电泳-安培检测法对甲基对硫磷、对硫磷、西维因和速灭威农药残留的测定研究

采用高效毛细管电泳 -安培检测法对农药甲基对硫磷、对硫磷、西维因和速灭威水解产物酚类进行了测定研究 ,考察了影响水解和毛细管分离的各种因素 :磷酸盐缓冲溶液的浓度、体系的 pH值、分离高压、检测电位等。结果表明 :在优化的实验条件下 ,标准样品15min内实现了基线分离 ,线性范围(mg/L) :间_甲酚、α_萘酚和对硝基苯酚均为0.05～10 ,信噪比为3时 ,测定检出限(mg/L) :间_甲酚0.04 ,α_萘酚0.02 ,对硝基苯酚0.03 ;对硫磷、速灭威和西维因回收率分别为91 % ,94%和101 % ,相对标准偏差分别为3.3 %、2.5 %和2.2 %(n=6)。

地骨皮中生物活性成分的毛细管区带电泳-安培检测方法研究

采用毛细管区带电泳-安培检测法(CZE-AD)同时分离测定了中药地骨皮中刺槐素、莨菪亭、山奈酚、对香豆酸、香草酸、木犀草素和槲皮素等多种生物活性成分, 考察了运行液酸度和浓度、分离电压、氧化电位和进样时间等实验参数对分离、检测体系的影响.在最佳实验条件下,以直径300 μm的碳圆盘电极为工作电极,检测电位为950 mV(vs. SCE),在80 mmol/L的硼砂缓冲溶液(pH 9.0)中,7组分在24 min可实现基线分离.7组分峰电流与其浓度在1.0×10-3～1.0×10-1范围内呈良好线性,检出限(S/N=3)达3.5×10-5～6.0×10-5 g/L.该方法成功地应用于中药地骨皮中生物活性成分的含量检测.

毛细管电泳-安培法测定复方磺胺甲噁唑片中的有效成分

采用毛细管电泳-安培法（CE-AD）同时分离测定了磺胺甲嗯唑（sulfamethoxazole，SMZ）、磺胺嘧啶（sulfadiazine，SD）和抗菌增效剂甲氧苄胺嘧啶（trimethoprim，TMP）3种常用磺胺类抗菌药物成分，考察了实验参数对分离、检测体系的影响。在优化实验条件下，以φ300μm碳圆盘电极作为工作电极，检测电位为1050mV（vs．SCE），在Na2B4O7（13mmol／L）-KH2PO4（18mmol／L）（pH5．8）的缓冲溶液中，分离电压18kV，进样6s，3组分在14min内可实现基线分离。上述3组分浓度分别在5×10^-4－5×10^-2、5×10^-4－0．1和5×10^-4－5×10^-2g／L范围内与其峰电流强度呈线性关系，检出限达5．1×10^-5－8．0×10^-5g／L（S／N=3）。该方法已成功应用于复方磺胺甲嗯唑片中抗菌活性成分的含量测定，结果令人满意。

手性药物异丙嗪对映体的毛细管电泳-方波安培法检测

以未涂层融硅石英毛细管 (5 0cm× 75 μm)为分离柱 ,5mmol/LNaOH +10mmol/LCitricacid +3mmol/LH3 BO3 +10mmol/L β 环糊精 (β CD) (pH =3.5 )为电泳介质 ,分离电压 12kV ,采用毛细管电泳 方波安培法对手性药物异丙嗪对映体实现了分离检测。对影响手性对映体分离检测效果的缓冲溶液的种类、浓度和 pH等诸因素进行了研究。结果表明 :硼酸与手性选择剂 β CD分子中糖羟基发生键合配位作用 ,增加了β CD 的负电性的特性 ,在对映体拆分中起到关键性的作用。

高效毛细管电泳-安培法同时检测感冒药中的扑尔敏、扑热息痛和维生素C

以碳糊电极作工作电极，采用高效毛细管电泳安培法对感冒药中的扑尔敏、扑热息痛和维生素 Ｃ 的同时检测进行了研究。重点探讨了检测电位、缓冲溶液添加剂对分离检测的影响。结果表明，方法简便、灵敏，适合于常规分析。

毛细管电泳-安培检测法测定女贞子中齐墩果酸的含量

女贞子又名冬青子,性凉,味甘、微苦,归肝、肾经,具有滋补肝肾、明目乌发的功能。女贞子主要有效成份为齐墩果酸Oleanolic Acid（OA）[1],其化学结构式如图1所示。OA是天然产物化学成分,毒性很低,具有多种生物活性如抗病毒、消炎、增强免疫和抑制免疫、抑制血小板凝集、降血脂、降糖、保肝、护肾、抗艾滋病毒等[2],故测定其含量可为药品的含量控制提供科学依据。

递质氨基酸的毛细管电泳-安培检测

研究了毛细管电泳安培检测氨基酸的方法。氨基酸用萘 -2,3 -二羧醛 (NDA)衍生为电活性物质。碳纤维电极采用1.5V ,30s固定电压电化学预处理 ,检测结果令人满意。作者还对最佳衍生反应条件 ,电极预处理条件对氨基酸衍生物电化学行为的影响进行了研究。该法对谷氨酸、甘氨酸、丙氨酸、γ -氨基丁酸的检出限分别为2.5×10-7、2.5×10-7、5.0×10-8、2.5×10-7 mol/L。