نتایج جستجو برای: derivatization

تعداد نتایج: 3729  

Journal: :Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 2011
M D Luque de Castro F Priego-Capote A Peralbo-Molina

Ultrasound is a type of energy that until recently was rarely used for analytical purposes. In recent years, work in chemical and industrial fields alerted analytical chemists to the great potential of ultrasonic energy to accelerate or improve different steps of the analytical process. One of these steps is derivatization: depolymerization, redox, hydrolysis, esterification, alkylation and com...

Journal: :Acta Crystallographica Section D Biological Crystallography 2003

Journal: :The Analyst 1998
R Herráez-Hernández P Campíns-Falcó L A Tortajada-Genaro

The enantiomeric determination of amphetamine and various amphetamine-type compounds by liquid chromatography after chiral derivatization with 9-fluorenylmethyl chloroformate-L-proline (FMOC-L-Pro) is reported. The results obtained were compared with those achieved after achiral derivatization with 9-fluorenylmethyl chloroformate and subsequent separation of the derivatives on a beta-cyclodextr...

Journal: :AppliedChem 2022

The determination of the true molar mass distribution (MMD) lignin is highly important to understand physicochemical characteristics for lignin-based value-added applications. It imperative develop a universal method quantify accurate MMD using size exclusion chromatography (SEC), as conventional with polymer standards provides irregular results. This work aims evaluate five samples (Protobind ...

Journal: :Analytical and bioanalytical chemistry 2008
María Gómez-Brandón Marta Lores Jorge Domínguez

This study involved comparison of different extraction and derivatization methods for determining FAs in soil and in four highly organic matrixes (cattle manure, pig slurry, compost, and vermicompost), by application of a multifactor categorical design. Although some studies have been carried out regarding the application of FA analysis to highly organic matrixes, comparison and verification ar...

Journal: :Drug discoveries & therapeutics 2007
T Santa O Y Al-Dirbashi T Fukushima

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESIMS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is frequently used to enhance the MS/MS detectability. The derivatization improves the separation and ionization efficiency. Moreover, the generated derivatives give par...

2000
Matthew H. Slawson Kimberly J. Shaw

A rapid, simple, and sensitive electrospray LC/MS method has been developed for the quantitative analysis of cocaine and benzoylecgonine in urine using electrospray with the Agilent 1100 LC/MSD system. Urine samples were extracted using solid phase extraction cartridges, and the drug and metabolite were analyzed without derivatization using an isocratic separation and selected ion monitoring (S...

Journal: :Journal of environmental sciences 2007
Yi-Qi Zhou Zi-Jian Wang Ning Jia

N,O-bis(trimethylsily)trifluoroacetamide (BSTFA) and N-methyl-N(trimethylsily) trifluoroacetamide (MSTFA) are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone (El) and 17alpha-ethinylestradiol (EE2). In this study, three trimethylsilyl (TMS) steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl E1, were observed during the der...

Mansoor Khordegir, Morteza Ziyaadini,

Abstract Reverse phase dispersive liquid- liquid microextraction (RP- DLLME) coupled with spectrophotometry is introduced for the detection of total phenol in the muscle tissue of fishes, such as Sphyraena genie, Otolithes ruber, Rastrelliger kangurta, Lutjanus johnii and Barbus Subquin Cunciatus. Phenols in fish tissues were extracted by ultrasonic bath and derivatization with 4- aminoant...

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