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Derivatization Reaction (derivatization + reaction)
Selected AbstractsDerivatization reaction of the mycotoxin moniliformin with 1,2-diamino-4,5-dichlorobenzene: structure elucidation of an unexpected reaction product by liquid chromatography/tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance spectroscopyJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2003Peter Zöllner Abstract The derivatization reaction of the mycotoxin moniliformin with 1,2-diamino-4,5-dichlorobenzene was previously introduced to improve distinctly the sensitivity of an assay applying high-performance liquid chromatography prior to fluorescence detection. In the course of the implementation of this derivatization approach into a liquid chromatographic/mass spectrometric method, an unexpected derivatization product has now been discovered by mass spectrometry. In order to elucidate its structure, detailed investigations with liquid chromatography/tandem mass spectrometry and liquid chromatography coupled on-line with NMR spectroscopy were performed. These studies give evidence for a heterocyclic structure that has been formed by the loss of one water and one carbon monoxide molecule. A reasonable mechanism for this derivatization reaction is proposed. Copyright © 2003 John Wiley & Sons, Ltd. [source] Simultaneous determination of memantine and amantadine in human plasma as fluorescein derivatives by micellar electrokinetic chromatography with laser-induced fluorescence detection and its clinical applicationELECTROPHORESIS, Issue 11 2010Hsin-Hua Yeh Abstract A nonionic surfactant MEKC method with LIF detection was developed for the simultaneous determination of memantine, an anti-Alzheimer's disease agent, and amantadine, an anti-Parkinson's disease drug, in human plasma. Before analysis, the plasma samples were pretreated by liquid,liquid extraction with ethyl acetate, and derivatized with 6-carboxyfluorescein N -hydroxysuccinimide ester. The chemical derivatization is performed with 6-carboxyfluorescein N -hydroxysuccinimide ester in ACN , 5,mM pH 9.0 borate buffer (40:60, v/v) at 35°C for 3,h. After the derivatization reaction, hydrodynamic injection (0.5,psi, 8,s) was used to introduce the derivatized solution, and the separation was performed in borate buffer (30,mM, pH 9.5) with the nonionic surfactant Brij-35® (0.07%, w/v); the separation voltage was 6,kV. The linear ranges of the method for the determination of memantine and amantadine in human plasma were over a range of 2.0,60.0,ng/mL. The detection limit was 0.5,ng/mL (S/N=3). This method was applied successfully to monitor the concentration of memantine or amantadine in patients with Alzheimer's disease or Parkinson's disease. [source] Fast derivatization of the non-protein amino acid ornithine with FITC using an ultrasound probe prior to enantiomeric determination in food supplements by EKCELECTROPHORESIS, Issue 6 2009Elena Domínguez-Vega Abstract An EKC method for the determination of ornithine (Orn) enantiomers has been developed after a fast pre-capillary derivatization with FITC. The derivatization step was needed to provide a chemical moiety to the Orn molecule, enabling a sensitive UV detection and the interaction with the CDs used as chiral selectors. To accelerate the derivatization reaction, an ultrasound probe was used. For the development of the chiral method, the influence of different experimental conditions (type and concentration of the chiral selector, temperature, and separation voltage) was investigated. Due to the anionic nature of the analyte (FITC-Orn), five neutral CDs were employed as chiral selectors. The native ,-CD showed the highest chiral separation power, observing that a low concentration of this CD (1,mM), using a working temperature of 25°C and a separation voltage of 20,kV, enabled to obtain the highest enantioresolution for Orn and its separation from other amino acids usually present in food supplements. After optimizing the method for the preconditioning of the capillary, the analytical characteristics of the chiral method were established. Linearity, LOD and LOQ, precision, and accuracy were evaluated previously to the determination of Orn enantiomers contained in ten commercial food supplements. No interferences from other amino acids present in these samples were observed. [source] Design, characterization, and utilization of a fast fluorescence derivatization reaction utilizing o -phthaldialdehyde coupled with fluorescent thiolsELECTROPHORESIS, Issue 7 2007Suminda Hapuarachchi Abstract We have developed a chemical derivatization scheme for primary amines that couples the fast kinetic properties of o -phthaldialdehyde (OPA) with the photophysical properties of visible, high quantum yield, fluorescent dyes. In this reaction, OPA is used as a cross-linking reagent in the labeling reaction of primary amines in the presence of a fluorescent thiol, 5-((2-(and-3)- S -(acetylmercapto)succinoyl)amino)fluorescein (SAMSA fluorescein), thereby incorporating fluorescein (,,=,78,000,M,1, quantum yield of 0.98) into the isoindole product. Detection is based on excitation and emission of the incorporated fluorescein using the 488,nm laser line of an Ar+ laser rather than the UV-excited isoindole, thereby eliminating the UV light sources for detection. Using this method, we have quantitatively labeled biologically important primary amines in less than 10,s. Detection limits for analysis of glutamate, glycine, GABA, and taurine were less than 2,nM. We present the characterization of OPA/SAMSA-F reaction and the potential utility of the derivatization reaction for dynamic chemical monitoring of biologically relevant analytes using CE. [source] Determination of biogenic amines in HeLa cell lysate by 6-oxy-(N -succinimidyl acetate)-9-(2',methoxycarbonyl) fluorescein and micellar electrokinetic capillary chromatography with laser-induced fluorescence detectionELECTROPHORESIS, Issue 4 2006Liwei Cao Abstract An MEKC-LIF method using 6-oxy-(N -succinimidyl acetate)-9-(2'-methoxy-carbonyl) fluorescein (SAMF) newly synthesized in our lab as a labeling reagent for the separation and determination of eight typical biogenic amines was proposed. After careful study of the derivatization condition such as pH value, reagent concentration, temperature, and reaction time, derivatization reaction was accomplished as quickly as 10,min with stable yield. Optimal separation of SAMF-labeled amines was achieved with a running buffer (pH,9.3) containing 30,mM boric acid, 25,mM SDS, and 20%,v/v ACN. The proposed method allowed biogenic amines to be determined with LODs as low as 0.25,2.5,nmol/L and RSD values from 0.4 to 4.5%. The present method has been successfully used to monitor biogenic amines in HeLa cells and fish samples. This study exploits the potential of MEKC-LIF with SAMF labeling as a tool for monitoring biogenic amines involved in complex physiological and behavioral processes in various matrices. [source] Analysis of amino acids in individual human erythrocytes by capillary electrophoresis with electroporation for intracellular derivatization and laser-induced fluorescence detectionELECTROPHORESIS, Issue 3 2004Hua Zhang Abstract A method for monitoring amino acids in single erythrocytes is described. For intracellular derivatization, reagent fluorescein isothiocyanate (FITC) was introduced into living cells by electroporation. For an 8 ,m erythrocyte, the analytes were diluted by a factor of only 1.6. After completion of the derivatization reaction, a single cell was injected into the separation capillary tip and lysed there. The derivatized amino acids were separated by capillary electrophoresis, followed by laser-induced fluorescence detection. Nine amino acids were quantitatively determined, with amounts of amino acids ranging from 3.8,32 amol/single cell. [source] Derivatization reaction of the mycotoxin moniliformin with 1,2-diamino-4,5-dichlorobenzene: structure elucidation of an unexpected reaction product by liquid chromatography/tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance spectroscopyJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2003Peter Zöllner Abstract The derivatization reaction of the mycotoxin moniliformin with 1,2-diamino-4,5-dichlorobenzene was previously introduced to improve distinctly the sensitivity of an assay applying high-performance liquid chromatography prior to fluorescence detection. In the course of the implementation of this derivatization approach into a liquid chromatographic/mass spectrometric method, an unexpected derivatization product has now been discovered by mass spectrometry. In order to elucidate its structure, detailed investigations with liquid chromatography/tandem mass spectrometry and liquid chromatography coupled on-line with NMR spectroscopy were performed. These studies give evidence for a heterocyclic structure that has been formed by the loss of one water and one carbon monoxide molecule. A reasonable mechanism for this derivatization reaction is proposed. Copyright © 2003 John Wiley & Sons, Ltd. [source] Potential determination of aminated pesticides and metabolites by cyclodextrin capillary electrophoresis,laser-induced fluorescence using FITC as labellingPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2005Miguel Navarrete-Casas Abstract 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 time and temperature) and those related with the separation itself (buffer concentration, addition of various organic modifiers, pH, applied voltage and injection time) were studied. The limit of detection obtained was between 0.45 and 3.48 µg litre,1 showing a relative standard deviation between 0.26 and 2.08% at a concentration level of 50 µg litre,1. Copyright © 2004 Society of Chemical Industry [source] Electrochemical Detection for Capillary Electrophoresis Microchips: A ReviewELECTROANALYSIS, Issue 13 2005Joseph Wang Abstract Electrochemistry detection offers considerable promise for capillary-electrophoresis (CE) microchips, with features that include remarkable sensitivity, portability, independence of optical path length or sample turbidity, low cost and power requirements, and high compatibility with modern micromachining technologies. This article highlights key strategies in controlled-potential electrochemical detectors for CE microchip systems, along with recent advances and directions. Subjects covered include the design of the electrochemical detection system, its requirements and operational principles, common electrode materials, isolation from the separation voltage, derivatization reactions, typical applications, and future prospects. It is expected that electrochemical detection will become a powerful tool for CE microchip systems and will lead to the creation of truly portable (and possibly disposable) devices. [source] Recent developments and applications of EMMA in enzymatic and derivatization reactionsELECTROPHORESIS, Issue 1 2010Jie Zhang Abstract This review covers the time period of 2007 until mid-2009 and describes new developments in the field of electrophoretically mediated microanalysis. The review is subdivided in two parts dealing with (i) enzymatic and (ii) derivatization or chemical reactions. A compilation of the relevant literature is given for each part. [source] Synthesis of Benzomorphan Analogues by Intramolecular Buchwald,Hartwig CyclizationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2007Anton S. Khartulyari Abstract A new strategy toward the important class of benzomorphans is described. The key bond formation is based on an intramolecular Buchwald,Hartwig enolate arylation reaction. Thus, alkylation of piperidones with ortho -bromobenzyl bromides provides the necessary substrates. In the presence of a palladium catalyst, a sterically hindered phosphane ligand, and a base, carbon,carbon bond formation to tricyclic benzomorphan derivatives takes place. After removal of the N -protecting group, derivatization reactions are possible. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Organosilica Materials with Bridging Phenyl Derivatives Incorporated into the Surfaces of Mesoporous Solids,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2008Andreas Kuschel Abstract An interesting class of materials is mesoporous organosilica materials containing a bridging, organic group along the pore-surface. Such materials are prepared from silsesquioxane precursors of the type (R,O)3Si-R-Si(OR,)3 where R is the bridging organic group of interest, in combination with a lyotropic phase as a template for the generation of the pores. A new silsesquioxane precursor, 1,3-bis-(trialkoxysilyl)-5-bromobenzene, and the related mesoporous organosilica material containing bromobenzene groups located at the pore walls are presented in the current publication. The latter precursor allows access to the derivatization reactions known for halogenated aromatic compounds. Materials containing phenyl derivatives can be obtained either by chemical modifications starting from the mentioned precursor on the molecular scale, or the modifications can be performed directly at the surfaces of the porous material. Materials with surfaces containing benzoic acid, styrene, and phenylphosphonic acid are described. [source] Detection of carbonyl groups in triterpenoids by hydroxylamine hydrochloride derivatization using electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2008Xin Liu A rapid, simple electrospray ionization mass spectrometry (ESI-MS) sensitivity enhancement method for detecting carbonyl groups in triterpenoids has been developed by using hydroxylamine hydrochloride (NH2OH,·,HCl) as a derivatization reagent. We use the oxime formed during the derivatization reactions and its Beckmann rearrangement intermediates as a means of detecting the carbonyl groups originally present in these triterpenoids. In comparison with other derivatization methods reported in the literature, this method is simple, specific and can be used to detect carbonyl groups in triterpenoids which have low polarity and are poorly or non-ionizable. Moreover, it can also be used to detect hydroxyl groups by using the Dess-Martin periodinane (DMP) to convert primary and secondary hydroxyls into carbonyl groups. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||