T14N2
Содержание
Determination of thiodiglycol and its oxide in biomedical samples by gas chromatography/mass spectrometry
T14N2
N.L. Koryagina, E.I. Savel’eva, N.S. Khlebnikova, A.S. Radilov
An unified procedure for the determination of thiodiglycol (TDG) and its oxide (TDGO) as markers of exposure to sulfur mustard (SM) in biomedical samples (urine, blood plasma, hairs) by means of gas chromatography/mass spectrometry with electron ionization was suggested. The detection limit of the procedure compares with the lowest level of endogenous TDG in biosamples (1 ng ml–1). Solid-phase microextraction of the derivatized analytes from the reaction mixture allows the reduction of the matrix effect. The procedure was used for the analysis of rat biosamples obtained after in vivo exposure to SM. The procedure was found to offer a higher potential in the retrospective determination of the total TDG and TDGO level in rat urine (within 7 days after exposure to 2 mg kg–1 SM) compared to the determination of the same markers of SM in blood plasma. Blood plasma can be used for confirmatory analysis, provided the samples are taken within 2 days after exposure. Hair were found to be the least suitable biomatrix in view of the variability of their background TDG level and the possibility of TDG contamination from other sources.
Peculiarities of mass spectrometric detection of anthocyanins in high-performance liquid chromatography
T14N2
V.I. Deineka, A.N. Sidorov, A.N. Chulkov, L.A. Deineka
The dependence of the fragmentation degree of anthocyanin “molecular” ions upon cone voltage of mass spectrometric electrospray/ionization detector was studied. It was found that the voltage required for the fragmentation of 50 % of the original “molecular” ions, Ef(0.5) increases with the number of glycoside residues. The fragmentation results in the removal of total glycoside residues regardless of their structures. In the case of 3.5-diglycosides, two types of fragment ions were formed due to the loss of glycosidic residues from different positions while the ratio of their peak intensities was opposite to that of the masses of neutrals eliminated. The values of Ef(0.5) for the monoglycosides (190 V), diglycosides (229 V), triglycosides (267 V), and for some acylated cyanidin-3,5-diglycosides were found. These results were given for gradient separation of anthocyanins by reverse phase HPLC in aqueous acetonitrile containing 10 vol. % of formic acid using a quadrupole mass spectrometric detection.
Phospholipid composition of human blood plasma as detected by matrix-assisted laser desorption/ionization mass spectrometry: new observations
T14N2
B.L. Milman, N.V. Lugovkina, I.K. Zhurkovich
The dependence of matrix-assisted laser desorption/ionization (MALDI) mass spectra of lipids extracted from human blood plasma and corresponding lipid compositions on different experimental conditions was studied. Not only numerous compounds from groups of lysophosphatidylcholines (LPC) and phosphatidylcholines (PC) but also lipid oxidation products including six oxidized LPC, were detected. They were available in the original samples and also produced by the reaction with air oxygen molecules resulted in their accumulation in samples under analysis. A higher sensitivity of MALDI detection was observed for less hydrophobic LPC as compared to more hydrophobic PC and was explained. The hydrophobicity/lipophilicity factor was possibly revealed when the matrix of 2,5-dihydroxybenzoic acid has been replaced by α-cyano-4-hydroxycinnamic acid. The latter was rarely used in MALDI of lipids and may be suitable for the selective determination of LPC and oxidized LPC.
Microextraction of aromatic microbial metabolites by packed sorbent (MEPS) from water solutions followed by gas chromatography/mass spectrometric analysis of their silyl derivatives
T14N2
P.D. Sobolev, A.K. Pautova, A.I. Revelsky
The paper describes the results of extraction of aromatic microbial metabolites (phenylcarboxylic acids) from model water solutions using microextraction by packed sorbent (MEPS) followed by the determination of their silyl derivatives with the aid of gas chromatography/mass spectrometry. The developed sorption-desorption, derivatization and gas chromatography determination conditions allows to detect a number of compounds, which are established and prospective disease markers. This detection could be performed at the level of their content in blood of healthy donors (0.5 μmol L–1) and in patients with an initial stage of sepsis (2–3 μmol L–1) and other serious diseases caused by significant microbial load and led to the development of multiple organ failure in intensive care unit patients. Recoveries of phenylcarboxylic acids using nonpolar sorbent (C18) reached 20–65% for hydroxylated acids (phenyllactic, 4-hydroxybenzoic, 4-hydroxyphenylacetic, 4-hydroxyphenylpropanoic, homovanillic and 4-hydroxyphenyllactic) and 100% for more nonpolar asids (benzoic, phenylpropanoic, cinnamic).
Application of PLS Discriminant Analysis to establish the absence of compound in electron ionization mass spectral database
T14N2
K.M. Sotnezova, A.S. Samokhin, I.A. Revelsky
Mathematical model has been developed to establish the absence of identified compound in electron ionization mass spectral library. The mathematical model (developed on the basis of PLS Discriminant Analysis) can be represented as a “black box” that provides an answer – the compound is absent in the database or not. Match factors of top ten candidates in the list of possible candidates were used as input data. More than 5000 objects (mass spectra) were used during training, validation and testing stages. Developed classification model provides correct prediction (that compound is absent in the library) in 28.4%, while only 1.2% of compounds that are represented in the database incorrectly classified as absent.
Features of the first and second order electrospray ionization mass spectra of salt-like products derived from mono and diols with the aid of combined reagents on the basis of ω-bromoacyl chlorides and nitrogen bases
T14N2
V.V. Ilyushenkova, L.N.Kulikova, R.S. Borisov, V.G. Zaikin
The paper describes the results of application of derivatization by composite reagents on the basis of ω-bromoacyl chlorides [ClCO(CH2)nBr (n=1-4)] and pyridine for the investigation of aliphatic and alicyclic alcohols and diols by ordinary and tandem electrospray/ionization (ESI) mass spectrometry. The applied derivatization involves the simultaneous acylation of hydroxyl groups by acyl chloride part of a reagent and quaternization of pyridine by bromoalkyl end group. Under the ESI conditions, quaternary salts produce corresponding mono and diammonium cations that appear in first order mass spectra. Collision induced dissociation (CID) of primary cations generated from monool derivatives gives rise to ammonium cations of corresponding acids HOOC(CH2)n-N+(C5H5). CID of primary dications gives rise to the same cations which are also eliminated from dications to form mono-charged fragments.
Predictive liquid chromatography of peptides based on hydrophilic interactions for mass spectrometry-based proteomics
T14N2
A.A. Lobas, L.I. Levitsky, A. Fichtenbaum, A.K. Surin, M.L. Pridatchenko, G. Mitulović,
A.V. Gorshkov, M. V. Gorshkov
High-performance liquid chromatography (HPLC) is widely used for separation of complex peptide mixtures before mass spectrometry-based proteome analysis. In such analysis, reversed phase HPLC (RP-HPLC) using non-polar stationary phases such as surface-modified silica containing alkyl groups (e.g., C18) is typically employed. Because of the high heterogeneity of proteomic samples, multidimensional separation approaches gained increasing attention recently to tackle this complexity and extremely high range of concentrations. In two-dimensional liquid chromatography, hydrophilic interaction chromatography (HILIC) is often a method of choice for combination with RP-HPLC because it uses reversed-phase type of eluents and allows efficient separation of polar peptides. Due to the high degree of orthogonality in this two-dimensional separation space, it is tempting to develop approaches for predicting peptide retention times for HILIC-based separations similar to the ones for RP-HPLC. Recent successful efforts in this area were focused on developing retention coefficient (RC)-based approaches. Herein, we explored the feasibility of using a statistical thermodynamic model for prediction of peptide retention times in HILIC separations and determined the phenomenological parameters of the model for a bare silica column. The performance of the developed model was tested using HPLC-MS analysis of a set of synthetic peptides, as well as a tryptic peptide mixture.
Study of chlorination of UV-filter avobenzone in sea water by gas chromatography combined with high resolution mass spectrometry
T14N2
A.А. Chugunova, M. B. Kralj, O.V. Polyakova, V.B. Artaev, P. Trebše2, S.A. Pokryshkin,
A.T. Lebedev
Disinfection represents an important step to purify drinking water as well as swimming pool water. The most widespread procedure involves chlorination which efficiently eliminates micro organisms. However reaction of active chlorine with dissolved organic matter results in formation of numerous organochlorine compounds representing certain hazard for environment and human health. UV-filters belong to emerging contaminants as their application for the skin protection from UV-irradiation becomes more and more popular all over the world. Certain components of UV-filters appear in swimming pools forming new ecotoxicants. In the present study 40 compounds including numerous brominated derivatives forming due to avobenzone chlorination in the sea water are identified by means of gas chromatography/high resolution mass spectrometry. In addition, the applicability of photocatalysis to destroy the forming products was checked. The procedure appeared to be rather efficient. It allows one to decrease the total quantity of avobenzone transformation products by a factor of 10. The only class of compounds demonstrating its stability in the applied conditions is halogenated derivatives of acetophenone.
