نتایج جستجو برای: derivatization

تعداد نتایج: 3729  

Journal: :European journal of mass spectrometry 2005
Vladimir G Zaikin John M Halket

The review describes chemical transformations of multifunctional compounds (amino acids and peptides, amino alcohols, amino thiols, hydroxy acids, oxo acids, oxo alcohols, compounds containing simultaneously three or more different groups etc.) by using step-wise or one-step modification or protection of functional groups. Some chemical aspects of mixed derivatization performed for improving th...

Journal: :Journal of chromatography. A 1996
H Kataoka

The environmental analysis of amines is important to preserve human health because these compounds often have toxic effects. Gas chromatography (GC) of free amines is generally unsatisfactory owing to the adsorption and decomposition of the solutes on the column. Derivatization of amines is employed to reduce the polarity and to improve the GC properties. Derivatization reactions for the determ...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2010
Shingoro Shirai Yoshihiro Saito Yasuhiro Sakurai Ikuo Ueta Kiyokatsu Jinno

Surface derivatization of Kevlar, poly(p-phenylene terephthalamide), fiber has been studied along with the evaluation of the surface characteristics of the chemically-modified fiber as the stationary phase in packed-capillary gas chromatography (GC). Several experimental parameters in the derivatization reaction have been optimized, and the retention behavior of the surface-derivatized fibrous ...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2005
Kyoung Suk Kim Ryota Shinohara Koji Arizono Yoshinori Kanetsuna Minoru Koga

A rapid and sensitive analytical method using pentafluorothiophenol (PFTP) derivatization was applied to detect diphenylarsinic acid (DPAA) in water. In this study, the optimum derivatization conditions, such as acid concentration, reaction time and reaction temperature, were investigated to develop a suitable procedure for DPAA determination. After extracting the derivatives into benzene, the ...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2003
Tatsuya Higashi Akinori Yamauchi Kazutake Shimada

The utility of 4-(4-nitrophenyl)-1,2,4-triazoline-3,5-dione (NPTAD) as a derivatization reagent in the analysis of 25-hydroxyvitamin D3 [25(OH)D3] using liquid chromatography/electron capture atmospheric pressure chemical ionization-mass spectrometry (LC/ECAPCI-MS) was examined. The derivatives of 25(OH)D3 with NPTAD underwent electron capture in the APCI source in the negative-ion mode and pro...

Journal: :Methods in molecular biology 2013
Yuqing Chang Bo Yang Amanda Weyers Robert J Linhardt

Capillary electrophoresis is a common technique used for glycosaminoglycan-derived disaccharide analysis because of its high resolving power, high separation efficiency, high sensitivity, short analysis time, and straightforward operation. CE coupled to laser-induced fluorescence (LIF) detection shows an approximately 100 times higher sensitivity than traditional UV detection at 232 nm. 2-Amino...

2005

• Here we present an N-terminal derivatization approach, using TMPP-Ac-Osu that improves the HPLC performance for small hydrophilic phosphopeptides. • This approach is compatible with LC/MS and LC/MALDI. • The chromatographic enhancement was evaluated by on-line nanoscale HPLC coupled with Electrospray on a Q-Tof PremierTM. • LC-MALDI/MS/MS analysis was also investigated. Both MS/MS on a Q-Tof ...

Journal: :Pest management science 2005
Miguel Navarrete-Casas Antonio Segura-Carretero Carmen Cruces-Blanco Alberto Fernández-Gutiérrez

We describe a detailed study on the possibility of analyzing aminated pesticides and metabolites using pre-column derivatization with fluorescein isothiocyanate (FITC) and their subsequent separation and detection by cyclodextrin capillary electrophoresis-laser-induced fluorescence (CE-LIF) detection. Different variables affecting the derivatization reaction (pH, FITC concentration, reaction ti...

2013
Yao Xiao Udo Huber

The analysis of aflatoxins in food matrices such as grain and nuts is an important task for the food industry to ensure product safety. This Application Note shows the analysis of the four major aflatoxins after sample preparation using an immunoaffinity column, post column UV derivatization, and fluorescence detection. We show that with this method the LOD and LOQ required from the regulatory ...

Journal: :Journal of chromatography. A 2007
Chih-Hung Wu Mei-Han Huang Sheng-Meng Wang Ching-Chiang Lin Ray H Liu

Method of chemical derivatization is the main difference among the GC-MS based methodologies reported for the analysis of ketamine and its major metabolites (norketamine and dehydronorketamine). These approaches included acylation and silylation resulting in the formation of acetyl, trifluoroacetyl, heptafluorobutyryl, and pentafluorobenzoyl (for acylation); and possibly trimethylsilyl and t-bu...

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