检索结果-内蒙古大学图书馆

Analysis of three- and four-way data using multivariate curve resolution-alternating least squares with global multi-way kinetic fitting

引用

CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS 2006年第1期81卷 82-93页

作者： Bezemer, E Rutan, SC Virginia Commonwealth Univ Dept Chem Richmond VA 23284 USA

This paper demonstrates a novel implementation of an alternating least squares (ALS) algorithm for resolving three- and four-way data. Computer-simulated multi-way data are studied as well as the multi-way data obtained from typical kinetic experiments observed using liquid chromatography with diode array detection (LC-DAD) and UV-visible spectroscopy. Each data set is analyzed using this new multi-way ALS algorithm, not only providing estimates of the spectral profiles (and retention profiles in the case of LC-DAD measurements) for each of the components involved, but also simultaneously estimating the rate constants for the reaction steps at different experimental conditions using a global kinetic analysis. However, when the reaction conditions do not require that all the rate constants are identical for each experiment, as is the case when the reactions are observed at different temperatures, the data analysis still benefits from the common information present in the data, such as spectral and retention profiles, as well as a common reaction mechanism. (c) 2005 Elsevier B.V. All rights reserved.

关键词： kinetic constraint hydrolisis nonlinear regression liquid chromatography diode array detection

来源：评论

学校读者我要写书评

暂无评论

Polyphenolic profile characterization of Agrimonia eupatoria L. by HPLC with different detection devices

引用

BIOMEDICAL CHROMATOGRAPHY 2006年第1期20卷 88-94页

作者： Correia, H González-Paramás, A Amaral, MT Santos-Buelga, C Batista, MT Univ Coimbra Lab Farmacognosia Fac Farm P-3000295 Coimbra Portugal Univ Coimbra Lab Farmacognosia Ctr Estudos Farmaceut P-3000295 Coimbra Portugal Univ Salamanca Fac Farm Unidad Nutr & Bromatol E-37007 Salamanca Spain

Liquid chromatography coupled to diode array and electrospray ionization mass spectrometry detection was used to establish the polyphenolic profile of an ethyl acetate fraction from Agrimonia eupatoria L. aqueous-alcoholic extract. Additionally, an HPLC technique with post-column derivatization by p-dimethylaminocinnamaldehyde was employed for the selective detection and quantification of flavan-3-ols. Important information was obtained by combining the data of these two HPLC techniques. Flavan-3-ols (catechin and procyanidins B1, B2, B3, B6, B7, C1, C2 and epicatechin-epicatechin-catechin), quercetin 3-O-glucoside, quercetin 3-O-galactoside, kaempferol 3-O-glucoside, kaempferol 3-O-(6"-O-p-coumaroyl)-glucoside, apigenin 6-C-glucoside and various phenolic acids were identified. Antioxidant activity of the Agrimonia eupatoria L. fraction containing these compounds was assessed through the 1,1-diphenyl-2-picrylhydrazyl, trolox equivalent antioxidant capacity and thiobarbituric acid reactive substances methods. Significant activity was observed for this fraction, where compounds with recognized anti-inflammatory properties such as procyanidins, kaempferol 3-O-(6"-O-p-coumaroyl)-glucoside and quercetin glycosides were identified for the first time. These results are predictive of the beneficial effects of this fraction, or some of its compounds, in human health, as possible anti-inflammatory drug. Copyright (c) 2005 John Wiley & Sons, Ltd.

关键词： HPLC diode array detection ESI-MS/MS post-column derivatization Agrimonia eupatoria L. polyphenols

来源：评论

学校读者我要写书评

暂无评论

Solid phase extraction and HPLC determination of veterinary pharmaceuticals in wastewater

引用

TALANTA 2006年第4期70卷 732-738页

作者： Babic, Sandra Asperger, Danijela Mutavdzic, Dragana Horvat, Alka J. M. Kastelan-Macan, Marija Univ Zagreb Analyt Chem Lab Fac Chem Engn & Technol HR-10000 Zagreb Croatia

This work focuses on the application of SPE-HPLC analysis of important veterinary pharmaceuticals from different classes in highly complex wastewater matrix. The pharmaceutical investigated included three sulfonamides (sulfamethazine, sulfadiazine and sulfaguanidine), a sulfonamide synergist (trimethoprim), a tetracycline (oxytetracycline), a fluoroquinolone (enrofloxacine) and a beta-lactame (penicillin G/procaine). The method involves pre-concentration and clean-up by solid phase extraction (SPE) using Oasis HLB extraction catridges. Final analysis of the selected pharmaceutical compounds was carried out by high-performance liquid chromatography (HPLQ coupled with diode array detector (DAD). Recoveries were ranged from 68.3 to 97.9% with relative standard deviation below 8.4%. Only for sulfaguanidine low recovery was obtained. Limits of quantification were in the range 1.5-100 mu g/L depending on pharmaceutical. The described method was applied to the determination of pharmaceuticals in wastewater samples from pharmaceutical industry. (c) 2006 Elsevier B.V. All rights reserved.

关键词： pharmaceuticals wastewater high-performance liquid chromatography diode array detection solid-phase extraction

来源：评论

学校读者我要写书评

暂无评论

Determination of strychnine and brucine in Strychnos nux-vomica L. by nonaqueous capillary electrophoresis

引用

CHROMATOGRAPHIA 2006年第5-6期63卷 289-292页

作者： Gu, XX Li, HX Zhu, RH Zou, H Capital Normal Univ Dept Chem Beijing 100037 Peoples R China

A nonaqueous capillary electrophoresis method with photo diode-array detection was developed for the analysis of strychnine and brucine in Strychnos nux-vomica L. The separation of the two alkaloids was optimized with respect to the concentration of Tris-boric acid, the proportion of methanol and acetonitrile, and applied voltage. Baseline separation was obtained for the two analytes within 10 min using a running buffer containing 25 mM Tris-boric acid, 60% methanol and 20% acetonitrile with acetic acid adjusting pH to 4.0. In this paper, the method was used to determine the contents of strychnine and brucine in raw material and prepared Strychnos nuxvomica L.

关键词： capillary electrophoresis diode array detection Strychnos nux-vomica L. strychnine and brucine

来源：评论

学校读者我要写书评

暂无评论

Simultaneous determination of four phenolic compounds and tanshinone IIA in Guanxintong tablets by LC using combined electrochemical detection and DAD

引用

CHROMATOGRAPHIA 2006年第1-2期63卷 39-44页

作者： Zheng, JB Suo, ZR Liu, L NW Univ Xian Inst Analyt Sci Shaanxi Provincial Key Lab Electroanalyt Chem Xian 710069 Peoples R China

A rapid, sensitive and accurate method for the simultaneous separation and determination of four phenolic compounds, including protocatechuic acid, protocatechuic alclehyde, caffeic acid and ferulic acid, and tanshinone IIA in Guanxintong tablets by high performance liquid chromatography using combined electrochemical detection with diode array detection (HPLC-ECD-DAD) has been established. The detection and quantification limits of four phenolic compounds with ECD were 7-28 fold greater than those obtained with DAD. High sensitivity was achieved using DAD for the detection of tanshinone IIA, which is an electrochemically inactive compound. All calibration curves showed good linearity (r >= 0.9996) within the test ranges. The recoveries ranged from 96.5% to 101.7%. Combining ECD with DAD can not only exert their respective advantages, but also widen its applications to detect various analytes in low level directly. This approach can be used to control the quality of Guanxintong tablets.

关键词： column liquid chromatography electrochemical detection diode array detection phenolic compounds Tanskinone IIA Guanxintong tablets

来源：评论

学校读者我要写书评

暂无评论

Screening for folic acid content in vitamin-fortified beverages

引用

FOOD CONTROL 2006年第11期17卷 900-904页

作者： Perez-Prieto, S. Cancho-Grande, B. Garcia-Falcon, S. Simal-Gandara, J. Univ Vigo Fac Food Sci & Technol Analyt & Food Chem Dept Nutr & Bromatol Grp Orense Spain

A method based on solid phase extraction (SPE), and followed by liquid chromatographic separation with diode array detection (HPLC-DAD), is presented as a useful analytical tool in quality control departments in the beverage industry for the determination of folic acid in fortified beverages such as milks, fruit nectars, isotonic drinks and yoghurts. These fortified beverages are recommended for pregnant women who need a higher consumption of this vitamin to avoid neural tube defects in the babies to be born. The results obtained with 11 commercial fortified beverages generally agreed well with those reported on the labels, what is key when there is a need to satisfy folic acid daily recommendations. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： folic acid fortified beverages diode array detection liquid chromatography solid phase extraction

来源：评论

学校读者我要写书评

暂无评论

Separation and detection of peroxynitrite and its metabolites by capillary electrophoresis with UV detection

引用

JOURNAL OF CHROMATOGRAPHY A 2006年第2期1111卷 147-152页

作者： Frankenfeld, CN Rosenbaugh, MR Fogarty, BA Lunte, SM Univ Kansas Dept Pharmaceut Chem Lawrence KS 66047 USA Drake Univ Des Moines IA 50311 USA

A method for the separation and direct detection of peroxynitrite (ONOO-) and two of its degradation products, nitrite (NO2-) and nitrate (NO3-), using capillary electrophoresis with ultraviolet detection is described. The separation parameters were optimized and included electrokinetic injection, a run buffer consisting of 25 mM K2HPO4 7.5 mM DTAB, pH 12, and a field strength of -323 V/cm. A diode array UV detector was employed in these studies as it allowed the determination of all three species simultaneously. Nitrate and nitrite provided the maximum response at 214 nun while peroxynitrite generated the best response at 302 nm. All three species could be detected at 214 nm, while simultaneous detection at 214 and 302 nm positively identified each peak. (c) 2005 Elsevier B.V. All rights reserved.

关键词： capillary electrophoresis UV detection peroxynitrite nitrite nitrate diode array detection

来源：评论

学校读者我要写书评

暂无评论

Separation and detection of peroxynitrite and its metabolites by capillary electrophoresis with UV detection

Separation and detection of peroxynitrite and its metabolite...

引用

18th International Symposium on MicroScale Bioseparation (MSB 2005)

作者： Frankenfeld, CN Rosenbaugh, MR Fogarty, BA Lunte, SM Univ Kansas Dept Pharmaceut Chem Lawrence KS 66047 USA Drake Univ Des Moines IA 50311 USA

关键词： capillary electrophoresis UV detection peroxynitrite nitrite nitrate diode array detection

来源：评论

学校读者我要写书评

暂无评论

An analysis of avidin, biotin and their interaction at attomole levels by voltammetric and chromatographic techniques

引用

ANALYTICAL AND BIOANALYTICAL CHEMISTRY 2005年第6期381卷 1167-1178页

作者： Kizek, R Masarik, M Kramer, KJ Potesil, D Bailey, M Howard, JA Klejdus, B Mikelova, R Adam, V Trnkova, L Jelen, F Mendel Univ Brno Dept Chem & Biochem Zemedelska 1 Brno 61300 Czech Republic Acad Sci Czech Republ Inst Biophys Lab Biophys Chem & Mol Oncol CS-61265 Brno Czech Republic USDA ARS Grain Mkt & Prod Res Ctr Manhattan KS 66502 USA Fac Sci Dept Analyt Chem Brno 61137 Czech Republic ProdiGene Inc College Stn TX 77845 USA Fac Sci Dept Theoret & Phys Chem Brno 61137 Czech Republic

The electroanalytical determination of avidin in solution, in a carbon paste, and in a transgenic maize extract was performed in acidic medium at a carbon paste electrode (CPE). The oxidative voltammetric signal resulting from the presence of tyrosine and tryptophan in avidin was observed using square-wave voltammetry. The process could be used to determine avidin concentrations up to 3 fM (100 amol in 3 mu l drop) in solution, 700 fM (174 fmol in 250 mu l solution) in an avidin-modified electrode, and 174 nM in a maize seed extract. In the case of the avidin-modified CPE, several parameters were studied in order to optimize the measurements, such as electrode accumulation time, composition of the avidin-modified CPE, and the elution time of avidin. In addition, the avidin-modified electrode was used to detect biotin in solution (the detection limit was 7.6 pmol in a 6 mu l drop) and to detect biotin in a pharmaceutical drug after various solvent extraction procedures. Comparable studies for the detection of biotin were developed using HPLC with diode array detection (HPLC- DAD) and flow injection analysis with electrochemical detection, which allowed biotin to be detected at levels as low as 614 pM and 6.6 nM, respectively. The effects of applied potential, acetonitrile content, and flow rate of the mobile phase on the FIA-ED signal were also studied.

关键词： avidin biotin avidin-biotin technology square-wave voltammetry modified electrode high-performance liquid chromatography diode array detection electrochemical transfer technique carbon paste electrode drug analysis

来源：评论

学校读者我要写书评

暂无评论

Stability indicating RP-HPLC method for simultaneous determination of amlodipine and benazepril hydrochloride from their combination drug product

引用

JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2005年第1-2期39卷 147-155页

作者： Naidu, KR Kale, UN Shingare, MS Marathwada Univ Dept Chem Aurangabad 431004 Maharashtra India

A stability indicating reversed-phase HPLC method has been developed and subsequently validated for simultaneous estimation of amlodipine (AM) present as amlodipine besylate (AB), and benazepril hydrochloride (BH) from their combination product. The proposed RP-HPLC method utilizes a Zorbax SB C18, 5 mu m, 250 mm x 4.6 mm i.d. column, mobile phase consisting of phosphate buffer and acetonitrile in the proportion of 65:35 (v/v) with apparent pH adjusted to 7.0, and UV detection at 240 nm using a photodiode array detector. AB, BH, and their combination drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analysed by the proposed method. Peak homogeneity data of AM and 1314 peaks obtained using photodiode array detector, in the stressed sample chromatograms, demonstrated the specificity of the method for their estimation in presence of degradants. The described method was linear over a range of 6-14 mu g/ml for AM and 12-28 mu g/ml for BH. The mean recoveries were 99.91 and 100.53% for AM and BH, respectively. F-test and t-test at 95% confidence level were used to check the intermediate precision data obtained under different experimental setups;the calculated value was found to be less than critical value. (c) 2005 Published by Elsevier B.V.

关键词： stability indicating RP-HPLC amlodipine benazepril diode array detection

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：