نتایج جستجو برای: derivatization

تعداد نتایج: 3729  

2011
Stefanie Kellner Salifu Seidu-Larry Jürgen Burhenne Yuri Motorin Mark Helm

A multifunctional reagent based on a coumarin scaffold was developed for derivatization of naive RNA. The alkylating agent N3BC [7-azido-4-(bromomethyl)coumarin], obtained by Pechmann condensation, is selective for uridine. N3BC and its RNA conjugates are pre-fluorophores which permits controlled modular and stepwise RNA derivatization. The success of RNA alkylation by N3BC can be monitored by ...

2010
L. R. Ruhaak G. Zauner C. Huhn C. Bruggink A. M. Deelder M. Wuhrer

Most methods for the analysis of oligosaccharides from biological sources require a glycan derivatization step: glycans may be derivatized to introduce a chromophore or fluorophore, facilitating detection after chromatographic or electrophoretic separation. Derivatization can also be applied to link charged or hydrophobic groups at the reducing end to enhance glycan separation and mass-spectrom...

Journal: :The Journal of biological chemistry 1988
R C Morton G E Gerber

A reagent and a derivatization procedure have been developed which result in trimesylation of all -OH and -NH2 groups on proteins: serine, threonine, tyrosine, and lysine side chains are all completely derivatized. The parameters affecting the kinetics of trimesylation of serine, threonine, and tyrosine peptides were studied using dinitrophenylated peptides as model systems. Conditions for solu...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2001
Y Sun M Wada N Kuroda K Hirayama H Nakazawa K Nakashima

A highly sensitive and selective method for simultaneous determination of some hydroxyl group-containing endocrine disruptors, including bisphenol A (BPA), bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF) and 4-nonylphenol (4-NP), was developed. The method consists of precolumn derivatization of the analytes, solid-phase extraction (SPE) and subsequent chromatographic analysis by high-pe...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2011
Junichi Odo Yuto Sogawa Masahiko Inoguchi Akihito Hirai

The fluorescent derivatization of tryptophan metabolites (xanthurenic acid, nicotinic acid, picolinic acid, and 3-hydroxyanthranilic acid) by the catalytic activity of horseradish peroxidase (HRP) was investigated in the presence of excess H(2)O(2). Non-fluorescent xanthurenic acid (XA) and nicotinic acid (NA) were converted into a fluorescent compound with maximum excitation and emission wavel...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2002
Tatsuya Higashi Natsuko Takido Akinori Yamauchi Kazutake Shimada

Derivatization of neutral steroids for increasing sensitivity in liquid chromatography/negative atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) has been examined. Under APCI conditions, gas-phase electrons are provided by the corona discharge and captured by electron-affinitive compounds. In negative APCI-MS, therefore, ultrahigh sensitivity can be obtained by tagging neutr...

2012
Francis Orata

Derivatization reactions are meant to transform an analyte for detectability in Gas Chromatography (GC) or other instrumental analytical methods. Derivatization in GC analysis can be defined as a procedural technique that primarily modifies an analyte’s functionality in order to enable chromatographic separations. A modified analyte in this case will be the product, which is known as the deriva...

2010
Bruno Casetta

The Inborn Errors of Metabolism (IEM) screening protocol, using LC/MS/MS for the analysis of amino acids (AA) and acylcarnitines (AC), is now widely used. Despite its broad acceptance, there is an ongoing debate regarding the need for the derivatization step described in the original sample preparation procedure. The derivatization by butylation hampers the simplicity of the assay and some user...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2009
Hideyuki Yoshida Maki Sudo Kenichiro Todoroki Hitoshi Nohta Masatoshi Yamaguchi

An LC postcolumn derivatization method for determination of polythiols has been developed. This method involves separation using reversed-phase LC, postcolumn derivatization with N-(1-pyrenyl)maleimide, and excimer fluorescence detection. Analytes with a polythiol structure were converted into corresponding polypyrene-labeled derivatives, and the derivatives exhibited intramolecular excimer flu...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2018
Jiying Pei Yinghui Wang Kefu Yu

Quinones are a class of compounds having substantial toxicity and pharmacological function. This work has produced a derivatization method for quinone detection with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). Through introducing tags (methoxy) to the quinone structures, the ionization efficiencies of five quinones (p-benzoquinone (B...

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