Liquid chromatography (LC) on various stationary phases was used for the metabolite profile analysis of quercetin, rutin, isoquercitrin and taxifolin. The metabolites were obtained using an in vitro model system of human and rat hepatocytes in the form of cell suspensions and the primary cultures. For separations of the parent compounds and their metabolites, stationary phases based on C₁₈, C₈, cyanopropyl (CNP) or phenyl (PHE) modifications of silica were tested. CNP and PHE stationary phases operating in reversed-phase mode have been shown to be efficient for separation of parent flavonoids and their polar metabolites. Individual metabolites were identified on the basis of an elemental composition determination using electrospray ionization-quadrupole time-of-flight mass spectrometry (ESI-QqTOF MS) on-line connected with an LC system. Detailed analytical parameters such as retention times, selectivity, resolution of chromatographic peaks, MS fragmentation and UV-vis absorption maxima were determined for individual metabolites, namely for phase II biotransformation products. The predominant metabolites were methylated flavonols and flavonol glucuronides. The highest biotransformation rate was found with taxifolin, which was mainly converted to sulfates. The HPLC/ESI-QqTOF MS analyses revealed that quercetin and taxifolin were metabolized more extensively than the studied glycosides, rutin and isoquercitrin.

• MeSH
• biotransformace MeSH
• dospělí MeSH
• flavonoly analýza   metabolismus   MeSH
• hepatocyty chemie   metabolismus   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• kultivované buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• quercetin analogy a deriváty   analýza   metabolismus   MeSH
• senioři MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• vysokoúčinná kapalinová chromatografie přístrojové vybavení   metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• flavonoly MeSH
• quercetin MeSH
• taxifolin MeSH Prohlížeč

Cheeses are a group of fermented dairy products that are produced all over the world in various forms and flavours. Milk, especially sheep or goat milk, is still regarded as an expensive raw material in the world, which makes milk and milk products highly attractive as a fraud target. Most often, such fraud includes partial or complete substitution with cheaper sorts of milk (e.g. bovine milk). The aim of this work was to verify the authenticity of 27 cheeses commonly emerging on the Czech food market. The cheeses were distinguished on the basis of milk animal species origin. For this purpose, two mass spectrometry techniques were used: matrix-assisted laser desorption/ionization with time of flight mass spectrometry together with principal component analysis method and liquid chromatography coupled with electrospray ionization and quadrupole time-of-flight mass spectrometry. The results were a partial success, because the cheeses could only be partially distinguished with the first mass spectrometry technique probably because of the influence of some protein additive materials in cheeses. The second technique allowed for collecting higher quality results and thus appears to be highly suitable for the research task.

• Klíčová slova
• casein, cheese, mass spectrometry, milk,
• MeSH
• chromatografie kapalinová MeSH
• kaseiny chemie   MeSH
• mléko chemie   MeSH
• skot MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• sýr analýza   MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kaseiny MeSH

Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification.

• Klíčová slova
• Human plasma, Lipidomics, Lipids, Mass spectrometry, Retention behavior, Ultrahigh-performance liquid chromatography,
• MeSH
• časové faktory MeSH
• chromatografie s reverzní fází metody   MeSH
• erytrocyty chemie   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• lidé MeSH
• lipidy analýza   krev   chemie   moč   MeSH
• mozek - chemie MeSH
• prasata MeSH
• superkritická fluidní chromatografie MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• lipidy MeSH

The aim of this work is to offer an alternative or complementary analytical tool to the time-consuming and expensive methods commonly used for the recognition of animal species according to their hair. The paper introduces a simple and fast way for species differentiation of animal hairs called in-sample digestion. A total of 10 European animal species, including cat, cow, common degu, dog, fallow deer, goat, horse, sika deer, rabbit, roe deer, and 17 different breeds of dogs were examined using specific tryptic cleavage directly in hair followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and liquid chromatography-electrospray ionization quadrupole time of flight. Principal component analysis was used for the subsequent mass spectrometric data evaluation. This novel approach demonstrates the ability to distinguish among individual animal species, which is supported by finding characteristic m/z values obtained by the mass spectrometry for each animal species. The approach was successfully tested on two "blind" samples. On the other hand, the attempt to distinguish among hairs of different dog breeds has not been successful due to the very similar protein composition and their amino acid sequences.

• Klíčová slova
• animal hairs, characteristic peaks, mass spectrometry, principal component analysis, proteins,
• MeSH
• divoká zvířata * MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• koně MeSH
• králíci MeSH
• peptidy chemie   MeSH
• proteiny analýza   MeSH
• proteolýza MeSH
• psi MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice metody   MeSH
• vlasy, chlupy chemie   MeSH
• vysoká zvěř * MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• peptidy MeSH
• proteiny MeSH

This work demonstrates the application of electrospray ionization mass spectrometry (ESI-MS) using two different mass analyzers, ion trap and hybrid quadrupole time-of-flight (QqTOF) mass analyzer, for the structural characterization of Ni(II) complexes of Schiff bases of (S)-N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide with different amino acids. ESI enables the determination of molecular weight on the basis of rather simple positive-ion ESI mass spectra containing only protonated molecules and adducts with sodium or potassium ions. Fragmentation patterns are characterized by tandem mass spectrometric experiments, where both tandem mass analyzers provide complementary information. QqTOF data are used for the determination of elemental composition of individual ions due to mass accuracies always better than 3 ppm with the external calibration, while multistage tandem mass spectra obtained by the ion trap are suitable for studying the fragmentation paths. The novel aspect of our approach is the combination of mass accuracies and relative abundances of all isotopic peaks in isotopic clusters providing more powerful data for the structural characterization of organometallic compounds containing polyisotopic elements. The benefit of relative and absolute mean mass accuracies is demonstrated on the example of studied Ni(II) complexes.

• MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• nikl chemie   MeSH
• pyrrolidiny chemie   MeSH
• Schiffovy báze chemie   MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• tryptofan chemie   MeSH
• tyrosin chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• (S)-N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide MeSH Prohlížeč
• nickel nitrate MeSH Prohlížeč
• nikl MeSH
• pyrrolidiny MeSH
• Schiffovy báze MeSH
• tryptofan MeSH
• tyrosin MeSH

A library of negative ion electrospray ionization mass spectra and tandem mass spectra (MS/MS) of sulfonated dyes has been developed for fast identification purposes. The uniform protocol has been elaborated and applied to the measurements of more than 50 anionic dyes. Three collision energies are selected in our protocol which ensures that at least one of them provides a suitable ratio of product ions to the precursor ion. The robustness is investigated with altered values of tuning parameters (e.g. the pressure of the nebulizing gas, the temperature and the flow rate of drying gas, and the mobile phase composition). The results of the inter-laboratory comparison of product ion mass spectra recorded on seven different tandem mass spectrometers (three ion traps, two triple quadrupoles and two hybrid quadrupole time of flight instruments) are presented for four representative anionic dyes--azo dye Acid Red 118, anthraquinone dye Acid Violet 43, triphenylmethane dye Acid Blue 1 and Al(III) metal-complex azo dye. The fragmentation patterns are almost identical for all tandem mass analyzers, only the ratios of product ions differ somewhat which confirms the possibility of spectra transfer among different mass analyzers with the goal of library formation.

• MeSH
• alkylsulfonany chemie   MeSH
• anthrachinony chemie   MeSH
• azosloučeniny chemie   MeSH
• barvicí látky chemie   MeSH
• benzensulfonáty chemie   MeSH
• databáze faktografické * MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací * MeSH
• referenční hodnoty MeSH
• rosanilinová barviva chemie   MeSH
• tandemová hmotnostní spektrometrie přístrojové vybavení   metody   MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• Acid Violet 43 MeSH Prohlížeč
• alkylsulfonany MeSH
• anthrachinony MeSH
• azosloučeniny MeSH
• barvicí látky MeSH
• benzensulfonáty MeSH
• rosanilinová barviva MeSH
• sulfan blue MeSH Prohlížeč

Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (MS) and an alternative technology represented by direct analysis in real time coupled with quadrupole time-of-flight MS were investigated for metabolic fingerprinting of 343 red and white wine samples. Direct injection of pure wine and an extraction procedure optimized for isolation of polyphenols were used to compare different analytical and data handling strategies. After data processing and data pretreatment, principal component analysis was initially used to explore the data structure. Initially, the unsupervised models revealed a notable clustering according to the grape varieties, and therefore supervised orthogonal partial least squares discriminant analysis models were created and validated for separation of red and white wines according to the grape variety. The validated orthogonal partial least squares discriminant analysis models based on data (ions) recorded in positive ionization mode were able to classify correctly 95% of samples. In parallel, authentication parameters, such as origin and vintage, were evaluated, and they are discussed. A tentative identification of markers was performed using accurate mass measurement of MS and MS/MS spectra, different software packages and different online libraries. In this way, different flavonol glucosides and polyphenols were identified as wine markers according to the grape varieties.

• MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• víno analýza   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• validační studie MeSH

Silver-ion high-performance liquid chromatography (HPLC) coupled to atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is used for the regioisomeric analysis of triacylglycerols (TGs). Standard mixtures of TG regioisomers are prepared by the randomization reaction from 8 mono-acid TG standards (tripalmitin, tristearin, triarachidin, triolein, trielaidin, trilinolein, trilinolenin and tri-gamma-linolenin). In total, 32 different regioisomeric doublets and 11 triplets are synthesized, separated by silver-ion HPLC using three serial coupled chromatographic columns giving a total length of 75cm. The retention of TGs increases strongly with the double bond (DB) number and slightly for regioisomers having more DBs in sn-1/3 positions. DB positional isomers (linolenic vs. γ-linolenic acids) are also separated and their reverse retention order in two different mobile phases is demonstrated. APCI mass spectra of all separated regioisomers are measured on five different mass spectrometers: single quadrupole LC/MSD (Agilent Technologies), triple quadrupole API 3000 (AB SCIEX), ion trap Esquire 3000 (Bruker Daltonics), quadrupole time-of-flight micrOTOF-Q (Bruker Daltonics) and LTQ Orbitrap XL (Thermo Fisher Scientific). The effect of different types of mass analyzer on the ratio of [M+H-R(i)COOH](+) fragment ions in APCI mass spectra is lower compared to the effect of the number of DBs, their position on the acyl chain and the regiospecific distribution of acyl chains on the glycerol skeleton. Presented data on [M+H-R(i)COOH](+) ratios measured on five different mass analyzers can be used for the direct regioisomeric determination in natural and biological samples.

• MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• hmotnostní spektrometrie metody   MeSH
• isomerie MeSH
• molekulová hmotnost MeSH
• triglyceridy chemie   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• triglyceridy MeSH

Di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) is a promising analogue of the dipyridyl thiosemicarbazone class currently under development as a potential anti-cancer drug. In fact, this class of agents shows markedly greater anti-tumor activity and selectivity than the clinically investigated thiosemicarbazone, Triapine®. However, further development of DpC requires detailed data concerning its metabolism. Therefore, we focused on the identification of principal phase I and II metabolites of DpC in vitro. DpC was incubated with human liver microsomes/S9 fractions and the samples were analyzed using ultra-performance liquid chromatography (UPLC(TM)) with electrospray ionization quadrupole-time-of-flight (Q-TOF) mass spectrometry. An Acquity UPLC BEH C(18) column was implemented with 2 mM ammonium acetate and acetonitrile in gradient mode as the mobile phase. The chemical structures of metabolites were proposed based on the accurate mass measurement of the protonated molecules as well as their main product ions. Ten phase I and two phase II metabolites were detected and structurally described. The metabolism of DpC occurred via oxidation of the thiocarbonyl group, hydroxylation and N-demethylation, as well as the combination of these reactions. Conjugates of DpC and the metabolite, M10, with glucuronic acid were also observed as phase II metabolites. Neither sulfate nor glutathione conjugates were detected. This study provides the first information about the chemical structure of the principal metabolites of DpC, which supports the development of this promising anti-cancer drug and provides vital data for further pharmacokinetic and in vivo metabolism studies.

• MeSH
• antitumorózní látky chemie   metabolismus   MeSH
• jaterní mikrozomy metabolismus   MeSH
• lidé MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• thiosemikarbazony chemie   metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• thiosemikarbazony MeSH

Selected precursors and degradation products of chemical warfare agents namely N,N-dialkylaminoethane-2-ols, N,N-dialkylaminoethyl-2-chlorides and some of related N-quaternary salts were studied by means of electrospray ionization-multiple tandem mass spectrometry (ESI-MS(n)). Proposed structures were confirmed with accurate mass measurement. General fragmentation patterns of these compounds are discussed in detail and suggested processes are confirmed using deuterated standards. The typical processes are elimination of alkene, hydrogen chloride, or water, respectively. Besides, elimination of ethene from propyl chain under specific conditions was observed and unambiguously confirmed using exact mass measurement and labelled standard. The potential of mass spectrometry to distinguish the positional isomers occurring among the studied compounds is reviewed in detail using two different MS instruments (i.e. ion trap and hybrid quadrupole-time of flight (Q-TOF) analyzer). A new microcolumn liquid chromatography (microLC)/MS(n) method was designed for the cases where the resolution based solely on differences in fragmentation is not sufficient. Low retention of the derivatives on reversed phase (RP) was overcome by using addition of less typical ion pairing agent (1 mM/l, 3,5-dinitrobenzoic acid) to the mobile phase (mixture water : acetonitrile).

• MeSH
• chemické bojové látky analýza   MeSH
• chromatografie kapalinová MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• indikátory a reagencie MeSH
• isomerie MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• roztoky MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické bojové látky MeSH
• indikátory a reagencie MeSH
• roztoky MeSH