نتایج جستجو برای: derivatization

تعداد نتایج: 3729  

Journal: :Journal of chromatographic science 2007
Jian Bo Xiao Xin Yu Jiang Xiao Qing Chen

Two well known derivatization methods, butylation and methylation, are compared by gas chromatography (GC)-mass spectrometry (MS) to identify organic acids in Bayer liquors. These two derivatization methods should be combined together for the determination of the carboxylic acids. Twenty-four organic acids are identified by GC-MS and 13 organic acids are firstly found in Bayer liquors. The rete...

2011
LACRIMIOARA SENILA ADRIANA GOG MARIN SENILA CECILIA ROMAN LUMINITA SILAGHI-DUMITRESCU

The aim of this study was the development and validation of a new method for carbohydrates analyses obtained from woody biomass, as a step of bioethanol production. In this study, we have quantified carbohydrates in wood by gas chromatography (GC) after derivatization. Quantification of carbohydrates was made by liquid-liquid extraction, oximation and silylation and, finally, analysis by gas ch...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2006
Maki Onoda Takefumi Uchiyama Ken-Ichi Mawatari Kiyoko Kaneko Kazuya Nakagomi

A simple batch method for the fluorometric determination of hydrogen peroxide using phosphine-based fluorescent reagents has been developed. A rapid, mild and selective derivatization reaction was achieved by adding sodium tungstate dihydrate to the reaction mixture of hydrogen peroxide and a phosphine-based fluorescent reagent. When 4-diphenylphosphino-7-methylthio-2,1,3-benzoxadiazole was use...

Journal: :Journal of chromatography. A 1997
S M Bird H Ge P C Uden J F Tyson E Block E Denoyer

As part of an ongoing study to identify selenium compounds with cancer chemopreventive activity, extracts of selenium-enriched samples were analyzed by HPLC-inductively coupled plasma (ICP)-MS. Ion-exchange, ion pair and derivatization methods for reversed-phase HPLC were considered and advantages and disadvantages for each compared. Anion exchange allows separation of selenite and selenate, bu...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2004
Hideyuki Yoshida Fumio Ichinose Takashi Yoshitake Yukitaka Nakano Kenichiro Todoroki Hitoshi Nohta Masatoshi Yamaguchi

A highly sensitive and selective fluorometric method for the determination of histamine and histidine has been developed. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent followed by reversed-phase liquid chromatography. The analytes, containing two amino moieties in a molecule, were converted to the corresponding dipyrene-labeled deriv...

2003
TOMASZ ŚNIEGOCKI JAN ŻMUDZKI ANDRZEJ POSYNIAK STANISŁAW SEMENIUK

A sensitive and specific gas chromatographic-mass spectrometric method for the determination of clenbuterol in urine and liver samples is described. Prepared for confirmatory purposes, this method includes solid phase extraction for clean up of biological samples, derivatization and analysis of the clenbuterol derivatives in the selected ion monitoring mode. During the studies, six derivatizati...

Journal: :Analytical and bioanalytical chemistry 2007
Loïc Dayon Hubert H Girault

The derivatization of cysteine-containing peptides with benzoquinone compounds is rapid, quantitative and specific in acidic media. The conversion of cysteines into hydrophobic benzoquinone-adducted residues in peptides is used here to alter the chromatographic properties of cysteinyl peptides during liquid chromatography separation. The benzoquinone derivatization is shown to allow the accurat...

Journal: :Journal of The Serbian Chemical Society 2023

The report describes the development of methods for rapid and simple identification Adamsite in mobile laboratory conditions using a field gas chromatograph coupled with mass spectrometer. is chemical warfare agent unique properties that cannot be analysed without conversion to volatile derivative. Derivatization procedures 5 aliphatic thiols (ethanethiol, 1-propanethiol, 2-propanethiol, 1-buta...

Journal: :Chemical communications 2006
Iria Louzao José Manuel Seco Emilio Quiñoá Ricardo Riguera

Derivatization of aldehyde cyanohydrins as (R)- and (S)-MPA esters and comparison of the corresponding 1H- and 13C-NMR spectra allows the assignment of their absolute configuration.

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