Fixed-charge generation derivatization for analysis of thiols by «soft» ionization mass spectrometry methods
T16N1
A.V. Kozlov, R.S. Borisov, V.G. Zaikin
A new method for the fixed-charge generation derivatization of thiols of different structures by reaction with haloalkanes and dibromides was suggested. It was shown that 1,4-dibromobutane and 1,2-xylylene dibromide are the most effective alkylating agents, that provided the formation of stable five-membered ring with a positively charged sulfur atom. Such cations are readily detected by electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry methods. Sulfonium cations were further studied by tandem mass spectrometry using collision-induced dissociation (CID). Typical and specific directions of CID for cyclic cations formed from thiols of different structures were established. They can be used to identify and quantify the thiol analytes by the selected reaction monitoring method.
Novel reactive matrices for analysis of alcohols by matrix-assisted laser desorption/ioization mass spectrometry
T15N2
M.S. Slyundina, R.S. Borisov, V.G. Zaikin
The possibility of using a number of aromatic and heteroaromatic carboxylic acids and their halogen anhydrides as reactive matrix compounds for the analysis of alcohols of different structures by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been studied. It is shown that acylation of alcohols with nicotinic and quinoline-6-carboxylic acid chlorides makes it possible to obtain derivatives having a high desorption/ionization efficiency under MALDI conditions, and the free acids formed as a result of the hydrolysis of anhydrides act as matrix compounds. The proposed approach is tested on a number of aliphatic, alicyclic and aromatic alcohols.
Electron ionization mass spectra of trimethylsilyl-pentafluoropropionyl and trimethylsilyl-heptafluorobutyryl derivatives of β-adrenoreceptor modulators
T15N1
A.A. Samosorova*, Yu.A. Efimova
The paper presents proposals for mass spectrometric determination of beta-adrenoreceptor modulators by bifunctional derivatization with N-methyl-N- (trimethylsilyl)-trifluoroacetamide followed by acylation with pentafluoropropionic or heptafluorobutyric anhydrides with a description of the derivatives obtained.
Silylation with the generation of a fixed charge for the analysis of alcohols by MALDI and SALDI mass spectrometry
T15N1
D.I. Zhilyaev, L.G. Voskresensky, N.Yu. Polovkov, R.S. Borisov
A new method of derivatization of alcohols for their analysis by matrix-assisted laser desorption/ionization (MALDI) and surface-assisted laser desorption/ionization (SALDI) is proposed. The approach is based on the silylation of the analytes by bromomethylchlorodimethylsilane in the presence of tertiary amines to yield the fixed-charge containing derivatives. The proposed method was tested using aliphatic, terpenoid and steroid alcohols. MALDI and SALDI mass spectra of all derivatives contained intense ion peaks corresponding to their cationic parts.
A new post-chromatographic derivatization approach to identification of alcohols and phenols in complex mixtures by a combination of planar chromatography and matrix-assisted laser desorption/ionization mass spectrometry
T14N4
C.A. Esparza, N.Yu. Polovkov, R.S. Borisov, A.V. Varlamov, V.G. Zaikin
Simple and suitable approach for post-chromatographic derivatization in the analysis of mixtures of alcohols and phenols by combination of thin-layer chromatography and MALDI mass spectrometry was suggested for the first time. Chemical modification of analytes was accomplished by the treatment of eluted zones on thin-layer chromatograms by 3-bromopropionyl chloride in the presence of excess of a base (pyridine or triethylamine). The resulting derivatives contained a residue with fixed charge (ammonium fragment) that provided an efficient desorption of derivatized analytes from the sorbent layer during MALDI. It was shown that the suggested approach allows the recording of mass spectra with high signal/noise ratio and the detection of alcohols and phenols of different structures. Reproducibility of such MALDI mass spectra is rather high which predetermines a possibility to build the chromatogram curves using total or selected ion current and, hence, their visualization and treatment on quantitative level.
Determination of methylphosphonic acid in human blood plasma by high-performance liquid chromatography tandem mass spectrometry
T13N4
T.M. Baygildiev, I.A. Rodin, A.N. Stavrianidi, A.V. Braun, O.A. Shpigun, I.V. Rybalchenko
Using high performance liquid chromatography combined with tandem mass spectrometric detection, an approach for the determination of the most stable nerve agent biomarker, methylphosphonic acid, in human blood plasma has been developed. The proposed method is based on the derivatization reaction of methylphosphonic acid with p-bromophenacyl bromide. Optimization of conditions for human plasma sample preparation, mass spectrometric detection conditiones and gradient elution program has been performed. The proposed approach has demonstrated satisfactory reproducibility and selectivity of the determination, limit of detection for methylphosphonic acid in human plasma was 3 ng ml−1.
Mass spectrometry of analytical derivatives. 2. “Ortho” and “Para” effects in electron ionization mass spectra of derivatives of hydroxy, mercapto and amino benzoic acids
T13N2
Нино Гурамовна Тодуа, Анзор Иванович Микая
Derivatives requiring either anhydrous or aqueous reaction conditions were prepared for robust and reliable gas chromatography/mass spectrometry (GC/MS) characterization of hydroxyl, mercapto, and amino benzoic acids. Methylation and trialkylsilylation are employed for blocking the acidic function. Alkyl, trimethylsilyl, acetyl, perfluoroacyl and alkoxycarbonyl derivatization groups are introduced to hydroxyl, mercapto and amino functions. The electron ionization induced fragmentation characteristics of corresponding derivatives are explained by comparing the MS1 spectra of unlabeled compounds to their 2H and 13C labeled analogs, and analysis of collision-induced dissociation data from MS2 spectra. Competing fragmentation alternatives are identified and specific decomposition processes are detailed that characterize (a) ortho isomers due to interaction of vicinal functional substituents and (b) para isomers prone to forming para quinoid type structures. Skeletal and hydrogen rearrangements typical for methyl benzoates and the blocking groups are considered when discussing diagnostically important ions. Characteristic ions produced as a result of rearrangements in ortho isomers are classified, and skeletal rearrangements required to produce para quinoid type ions specific for para isomers are noted. Key ions for structure elucidation and differentiation of isomers for derivatives of substituted benzoic acids by GC/MS are suggested.
Tris(2,6-dimethoxyphenyl)methyl carbenium ion as charge derivatization agent for the analysis of primary amines by MALDI mass spectrometry
T12N4
A.P. Topolyan, D.A. Strizhevskaya, M.S. Slyundina, M.A. Belyaeva, O.M. Ivanova,
V.A. Korshun, A.V. Ustinov, I.V. Mikhura, A.A. Formanovsky, R.S. Borisov Читать полностью
Simple and easy approach to derivatization of alcohols for the investigation by ‘soft’ ionization mass spectrometry methods
T11N2
R.S. Borisov, N.Yu. Polovkov, D.I. Zhilyaev, V.G. Zaikin
A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences
