Search

Abstract The kernel idea for this paper came from our more recent development of a mass spectrometric model equation, based on stochastic dynamics. It treats quantitatively the experimental intensity of analytes and their fragment ions under soft ionization conditions. The effort has resulted to exact universally applicable and empirically testable relationship, between mass spectrometric stochastic dynamic diffusion and the intensity. A linear correlation at high level of statistical significance occurs between D SD and the corresponding quantum chemical diffusions, obtained within the Arrhenius' approximation. It provides bridge between experimental MS parameters and 3D structure of analyte ions. Furthermore, we have claimed that the total intensity of the ions is proportional to their D SD parameter according to our model equation; or I tot ~ D SD. As evident from the small–scale of our contributions, so far, the simplistic theoretical concept and corresponding model equation need to be translated into a broad practical employment, because of; there is extended the capability of mass spectrometry beyond its routine application as irreplaceable method for quantitative analysis to the analytical practice. The superior features of the mass spectrometric instrumentation can offer us a new perspective of looking at the implementation of the method to exact 3D structural analysis in condense phase. As far as any such statement should be strongly quantified from the point of view of the chemometrics, this work deals with application of our stochastic dynamic concept of mass spectrometric diffusion to structural analysis of complex ions of CuII–ion with glycylhomopentapeptide and its dimeric associates. The large difference in the coordination fashion of oligopeptides, and competitive fragment paths together with the variety of the coordination modes of CuII–ion; and accounting, in parallel, for the different oxidation states of copper allows for us to demonstrate the great capability of our theoretical concept, studying so challenging research area. The experimental design is based on high resolution electrospray ionization mass spectrometric data in positive operation mode. High accuracy ab initio and methods based on theory on functional of density are used. Both static and molecular dynamic methods are employed. Graphical abstract Unlabelled Image Highlights • Electrospray ionization mass spectrometric quantification of diffusion parameters • Stochastic dynamic approach for quantification of the mass spectrometric intensity • Complexes of CuII–ion with glycylhomopentapeptide and its oligomeric associates • 3D structural analysis [ABSTRACT FROM AUTHOR]

Abstract The focus on this paper is on to continue the research line taken in our more recent studies of mass spectrometric approaches treating quantitatively the intensity of analyte fragment peaks with respect to time within the own model equation, based on stochastic dynamics, and correlating between experimental diffusion parameters of ions and their 3D structures, when this approach is used complementary with high accuracy methods of quantum chemistry. Accordingly, the aims at the work will be undeniably presented. First, we will explore ESI–MS in solution, operating under positive mode and crystallographic data of a CuII–complex of glycine (cis –{[CuII(Gly) 2 ].H 2 O} (1)) in determining experimental MS diffusions of ions according to the aforementioned methodology. The correlative analysis to quantum chemical diffusions will be carried out, using the Arrhenius' approximation to the theoretical diffusion of charged species under soft–ionization MS conditions. Second, on the base on experimentally observed complex isotope shape of coordination species of ions of copper, a theoretical description of redox processes under ESI–MS conditions will be detailed. There is nothing irreconcilable between both goals, as far as, the experimental data convincingly argued that the relation to MS stochastic dynamic diffusions ⇔ quantum chemical diffusion parameters has direct bearing on how the analysis of the MS intensity of isotope sub–peaks within the aforementioned method can provide direct information about experimental 3D structure of the analyte in condense phase. The cis/trans isomerization of {[CuII(Gly) 2 ]} complex is discussed in detail correlating crystallographic data of (1) with ESI(+)–MS ones. A process of isomerization cis –{[CuII(gly) 2 ]0} → trans –{[CuII(gly) 2 +H]+} is proposed on the base on crystallographic and mass spectrometric data on (1). Graphical abstract Stochastic dynamic mass spectrometric diffusion as a tool for 3D structural determination of metal-organics. Image 1 [ABSTRACT FROM AUTHOR]

This paper provides experimental and theoretical study of reaction of [2 + 2] cycloaddition of substituted α–unsaturated isophorone dyes, involving high resolution electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) tandem mass spectrometric (MS/MS) analysis in solution and in gas–phase (GP) of substituted 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone and configurationally locked polyenes (CLP). The ab initio and density functional theoretical (DFT) examining provides information about molecular geometry, thermodynamics, kinetics and ionization potentials of sixty six isomers of dimeric dyes, including corresponding cis -anti- cis and cis -syn- cis head-to-tail and head-to-head forms. The comparative collision induced dissociation (CID) or collision activated MS and theoretical analyses carried out bring light into the mechanisms of competitive dimerization within the frame of 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone; molecular and environmental factors governing regioselectivity of reaction. The analyses involve both qualitative and quantitative kinetics and thermodynamics of experimental MS data along with corresponding theoretical examining of CLP dimers. As far as 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone and CLP dyes have already found an industrial scale application as non-linear optical materials (NLO) for THz wave generation and detection as well as pharmaceutics for treatment of and preventing of neurodegenerative diseases, this study has a strong transdisciplinary impact to many research fields as well as to still not well understood, but crucial to fields of organic synthesis and catalysis, molecular level fundamentals of chemical reactivity in gas– and condense phases. Following the latter lines of contributions of the work, we might hopefully expect that the prospective highlighted in this study should inspired further research effort devoted to correlative quantitative thermodynamic and kinetic CID mass spectrometric and quantum chemical analyses, which allow to improve the reaction effectiveness depending on the complexity of the wanted CLP scaffolds. [ABSTRACT FROM AUTHOR]

The present paper deals with quantitative kinetics and thermodynamics of collision induced dissociation (CID) reactions of piperazines under different experimental conditions together with a systematic description of effect of counter-ions on common MS fragment reactions of piperazines; and intra-molecular effect of quaternary cyclization of substituted piperazines yielding to quaternary salts. There are discussed quantitative model equations of rate constants as well as free Gibbs energies of series of m –independent CID fragment processes in GP, which have been evidenced experimentally. Both kinetic and thermodynamic parameters are also predicted by computational density functional theory (DFT) and ab initio both static and dynamic methods. The paper examines validity of Maxwell–Boltzmann distribution to non–Boltzmann CID processes in quantitatively as well. The experiments conducted within the latter framework yield to an excellent correspondence with theoretical quantum chemical modeling. The important property of presented model equations of reaction kinetics is the applicability in predicting unknown and assigning of known mass spectrometric (MS) patterns. The nature of “GP” continuum of CID–MS coupled scheme of measurements with electrospray ionization (ESI) source is discussed, performing parallel computations in gas–phase (GP) and polar continuum at different temperatures and ionic strengths. The effect of pressure is presented. The study contributes significantly to methodological and phenomenological developments of CID–MS and its analytical implementations for quantitative and structural analyses. It also demonstrates great prospective of a complementary application of experimental CID–MS and computational quantum chemistry studying chemical reactivity, among others. To a considerable extend this work underlies the place of computational quantum chemistry to the field of experimental analytical chemistry in particular highlighting the structural analysis. [ABSTRACT FROM AUTHOR]

An essential part of molecular scaffolds of organosilver(I) catalysing reactions of C–H bond activation and C–X (X = C or O) bond formation of polysubstituted benzoic acids in polar medium represent biphenyls, 6H-benzo-[ c ]-chromene[6]-one, chromeno[5,4,3-cde]chromene-5,10-dione, and 4,10-dioxa-pyrene-5,9-diones. A second strand of catalytic activity is in promoting synthesis of substituted quanterphenyls. This paper is a an extend of the systematic examining of catalytic activity of Ag I –containing intermediates of substituted benzoic acids, gaining insights by synthesis of oligomers, studying benzene-1,2,4-tricarboxylic acid (124BA) and benzene-1,3,5-tricarboxylic acid (135BA). Arguably, the optimization of the latter reactions need further effort in order to achieve the standard characteristics allowing their effective implementation as routine routs in the field of organic synthesis. The purpose of this part of the research is mass spectrometric (MS) quantitative kinetic and thermodynamic treatment of collision induced dissociation (CID) reactions comparing experimental reaction kinetics and energetics with quantum chemical modelling of MS fragment processes. Analyses - experimental and theoretical - include deuterium labelled oligomers as the most useful technique studying MS reaction mechanisms. More specifically we treat eight substituted quaterphenyls both experimentally and theoretically along with a set of one hundred twenty 3D molecular models of MS fragment species. Importantly, the detail understanding of the molecular mechanistic aspects of the reactions causing for obtaining of high functionalized oligomers allows an efficient optimization of synthetic roads studying polyfunctional derivatives. This knowledge is the kay to understanding why the obtaining of the oligomer derivatives depends on the positional isomerism of the starting reagents as clearly evidenced in this study. In this context the study is relevant to the fields of organometallic synthesis and catalysis as well as the polymers' chemistry. [ABSTRACT FROM AUTHOR]

The research draws on experimental and theoretical data about energetics and kinetics of mass spectrometric (MS) reactions of glycyl homopenta- ( G5) and glycyl homohexapeptides ( G6). It shows the great applicability of the methods of quantum chemistry to predict MS profile of peptides using energetics of collision induced dissociation (CID) fragment species. Mass spectrometry is among irreplaceable methods, providing unambiguous qualitative, quantitative and structural information about analytes, applicable to many scientific areas like environmental chemistry; food chemistry; medicinal chemistry; and more. Our study could be considered of substantial interdisciplinary significance, where MS proteomics is widely used. The experimental design involves electrospray ionization (ESI) and CID MS/MS. Theoretical design is based on ab initio and density functional theory (DFT) methods. Experimental MS and theoretical free Gibbs energies as well as rate constants of fragment reactions are compared. The thermodynamic encompasses gas-phase and polar continuum analysis, including polar protic and aprotic solvents within temperature T = 10-500 K; dielectric constant ε = 0-78, pH, and ionic strengths μ = 0.001-1.0 mol dm−1. There are computed and discussed 39 protonated forms of peptides at amide N- and -(NHC)= O centers; corresponding fragment ions studying their thermodynamic stability depending on experimental conditions. A correlation analysis between molecular conformations of parent ions and fragment species; their proton accepting ability and internal energy distribution is carried out. Data about ionization potentials (IPs) and electron affinities (EAs) are discussed, as well. [ABSTRACT FROM AUTHOR]

The paper provides a comprehensive study of lanthanide and actinide complexes to a matter of key area in the field of the chemistry, i.e. environmental analytical chemistry. The content has involved: ( i ) solution and sorption behaviour of lanthanides (Ln n+ , Ln = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Py, Ho, Er, Tm, Yb and Lu) onto Y(O)O(H) minerals (Y = Fe, Mn or Si); ( ii ) ligand exchange processes with participation of inorganic OH − , F − , Cl − , Br − , SO 4 2− , SO 3 2− , IO 3 − , NO 3 2− , CO 3 2− and/or HCO 3 − ligands as well as mixed ligand complexes, including solvent molecules such as {[LnOR] 2+ }, {[Ln(OR) 2 ] + } (R = CH 3 OH, CH 3 CH 2 CH 2 OH) and {[Ln(CH 3 CN) x (H 2 O) z ] 3+ } ( x = 6–8, z = 0–4); ( iii ) the actinide speciation has involved different oxidation states (+4)–(+6) and ions {[UOH] 3+ }, {[UX] 3+ } (X = F or Cl), {[UF x ] y+/- } ( x = 2–6, y = 0–2), {[U(CO 3 ) x ] y- } (x = 4 or 5, y = 4 or 6), {[U(SO 4 )] 2+ ], {[U(NO 3 )] 3+ }, {[U(NO 3 ) 2 ] 2+ }, [[UO 2 (CO 3 ) 3 ] 5- }, {[(UO 2 ) x (OH) z ] y+/- } ( x = 1–4, y = 1 or 2, z = 1–7), {[UO 2 F x ] y+/- } ( x = 1–4, y = 1 or 2), {[UO 2 (CO 3 ) x ] y- } ( x = 2, or 3, y = 2, or 4), {[(UO 2 ) 2 (CO 3 )(OH) 3 ] - }, {[(UO 2 ) 3 O(OH) 2 (HCO 3 )] + }, {[(UO 2 ) 11 (CO 3 ) 6 (OH) 12 ] 2- }, {[UO 2 (SO 4 ) x ] y- }, ( x = 2 or 3, y = 2 or 4), {[UO 2 SiO(OH) 3 ] + }, {[AnC x ] y+/- } (x,y = 1 and 2), {[CAnH] +/− }, {[C x An y ] 0 } (x,y = 2 and 3), {[AnH x ] y+ } (x = 1–3, y = 0–5), {[AnX n ] m+/- } (n = 1–6, m = 1–4, X = F − , Br − , I − ), {[AnO x F z ] y+/- } (x, z = 1 or 2, y = 0, 1 and 2), {[AnN x ] y+ } (x = 1 and 2), {[An x O z (OH) n ] y+/- } (x = 1–3, z = 1–4, y = 0, 1 or 2, n = 0 or 1) and An n+ (n = 0–6) at An = Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No and Lr, respectively. Correlation analysis between thermodynamic parameters, accounting for different surface interactions of adsorbed species and experimental mass spectrometric data, including liquid, semi–liquid and solid–state measurements in a large set of experimental conditions such as pH = 2–13, low and intermediate ionic strength, solvent type, ε = 0–78.0, variety of solvent proton accepting and donating numbers and T = 25–400 °C has carried out. [ABSTRACT FROM AUTHOR]

Recent strategies in molecular drugs-design shift efforts to nanomedicine . Large supra-molecular inclusion systems are implemented as therapeutics. The sophistication of design is based on major advances of cyclodextrins (CDs) as host molecules. They are friendly towards biological environment. CDs have good (bio)compatibility as well. CDs can form host–guest macromolecular systems incorporating small molecules with suitable shapes due to non–covalent interactions. Innovative strategies yield to polymeric nano-particles; micelles; linear polymers and/or CDs-functionalized dendrimeric nanostructures; nanofibers as well as hydrogels. Attractive are phosphorous containing ( bio )matrerials, having high selectivity toward biological active molecules. The non–covalent interactions in aquatic CD-systems contribute to stability of host–guest systems under physiological conditions, determining conformational preferences of host-CD macromolecule and guest small molecular template. In this paper we have reported complementation application of mass spectrometric (MS) and quantum chemical analysis of phosphorous chemically substituted γ-cyclodextrin hydrates γ-CDPO/nH 2 O (n ∊ [0–14]), studying neutral and polynegatively charged molecules as an effort to describe realistic a representative scale of physiological conditions. The binding affinity and molecular conformations are discussed. The 250 neutral and charged systems (γ-CDPOH m /nH 2 O, n ∊ [10][0,14], m ∊ [0,15], γ-CDPOH -8 /nH 2 O.8Na + , and γ-CDPOH -16 /nH 2 O.16Na + ) in four main domains of non–covalent hydrogen bonding interactions are studied. [ABSTRACT FROM AUTHOR]

The presence of tramadol in roots of Sarcocephalus latifolius trees in Northern Cameroon was recently attributed to point contamination with the synthetic compound. The synthetic origin of tramadol in the environment has now been unambiguously confirmed. Tramadol samples isolated from tramadol pills bought at a street market in downtown Maroua and highly contaminated soil at Houdouvou were analyzed by high-precision 14C measurements by accelerator mass spectrometry (14C AMS): Tramadol from the pills did not contain any radiocarbon, thus indicating that it had been synthesized from 14C-free petroleum-derived precursors. Crucially, tramadol isolated from the soil was also radiocarbon-free. As all biosynthetic plant compounds must contain radiocarbon levels close to that of the contemporary environment, these results thus confirm that tramadol isolated from the soil cannot be plant-derived. Analyses of S. latifolius seeds, in vitro grown plants, plants from different origins, and stable-isotope labeling experiments further confirmed that synthetic tramadol contaminates the environment. [ABSTRACT FROM AUTHOR]

Advanced analytical imaging techniques, including matrix-assisted laser desorption/ionization high-resolution mass spectrometry (MALDI-HRMS) imaging, can be used to visualize the distribution, localization, and dynamics of target compounds and their precursors with limited sample preparation. Herein we report an application of MALDI-HRMS imaging to map, in high spatial resolution, the accumulation of the medicinally important naphthodianthrone hypericin, its structural analogues and proposed precursors, and other crucial phytochemical constituents in the leaves of two hypericin-containing species, Hypericum perforatum and Hypericum olympicum. We also investigated Hypericum patulum, which does not contain hypericin or its protoforms. We focused on both the secretory (dark glands, translucent glands, secretory canals, laminar glands, and ventral glands) and the surrounding non-secretory tissues to clarify the site of biosynthesis and localization of hypericin, its possible precursors, and patterns of localization of other related compounds concomitant to the presence or absence of hypericin. Hypericin, pseudohypericin, and protohypericin accumulate in the dark glands. However, the precursor emodin not only accumulates in the dark glands but is also present outside the glands in both hypericin-containing species. In hypericin-lacking H. patulum, however, emodin typically accumulates only in the glands, thereby providing evidence that hypericin is possibly biosynthesized outside the dark glands and thereafter stored in them. The distribution and localization of related compounds were also evaluated and are discussed concomitant to the occurrence of hypericin. Our study provides the basis for further detailed investigation of hypericin biosynthesis by gene discovery and expression studies. [ABSTRACT FROM AUTHOR]

The work presented here refers firstly to solid-state UV-MALDI-Orbitrap-mass spectrometric analysis of fluroxypyr ( A) and triclopyr ( B) in soils under laboratory conditions. The experimental design has involved the following: (a) determination of analytes A and B in polycrystalline composites of organic materials 1- 7, based on 2-piperidine (pyrrolidine or piperazine)-1-yl-ethyl ammonium salts in order to determine the effect of sample preparation techniques on method performance using commercial herbicide formulations and (b) analysis of non-( X) and sterilized ( Y) soil samples ( i-fold rate 1, 10, 100, or 1,000; j-pesticide type A or B; k-time (0, 5, 10, 20, and 50 days) and l = 1-3 replicated samples) having clay content ∈ 5.0-12.0 %, silt ∈ 23.0-51.1 %, sand ∈ 7.2-72.0 %, and pH ∈ 4.0-8.1. In order to obtain a high representativeness of the data toward real-field experiments, the pollution scheme has involved 1-, 10-, 100-, and 1,000-fold rates. The firstfold rate has concentration of pollutant A of 2.639 × 10 g in 625 cm soil horizon of 0-25 cm (5 cm depth) according to registration report (PSM-Zulassungbericht) of German Federal Office of Consumer Protection and Food Safety (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit) 6337/26.10.2009. The experimental design has involved quincunx systematic statistical approach for collection of soil samples. The performance has been compared with the corresponding statistical variable obtained, using an independent HPLC-ESI-(APCI-)-MS/MS analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantitative mass spectrometry of enantiomers of steroids in mixture in solution. • Stochastic dynamics atmospheric pressure chemical ionization mass spectrometry. • Quantum chemical and mass spectrometric stereoselective 3D analysis of mixtures. • Mass sectrometric 3D molecular structural analysis of steroids in mixture. There is explored, herein, functional relation: Experimental mass spectrometric phenomenon, obeying a certain scientific law ⇔ 3D molecular conformations and electronic structures of analytes obtained for quantum chemical theories. The paper answers to questions: (a) What evidence claims these actual relations among measurable and theoretical parameters, experimental factors and molecular properties; (b) how the provided evidence is collected and used; and (c) how empirical proof relates to assign and explain mass spectrometric phenomena of steroids afforded by our innovative stochastic dynamic mass spectrometric formula, D″ SD = 2.6388.10−17.(–_I_2), quantum chemical 3D conformations, electronic structures and energetics of molecules, respectively. The paper address issue concerning empirical evidence at very high-to-exact level of assignment of 3D molecular conformations of steroids to experimental mass spectrometric fragment ions, accounting precisely for (i) effect of protonation; (ii) intramolecular rearrangement for A–D rings of steroidal skeleton and proton transfer effect, if any; in addition to (iii) examination of enantiomers of steroids in mixture with different stereochemistry, (R) and (S), of a set of six atoms of the molecular backbone of hydrocortisone (1), deoxycorticosterone (2), progesterone (3) and methyltestosterone (4), respectively. Results from testosterone (5) are discussed, as well. There are used ultra-high resolution atmospheric pressure chemical ionization mass spectrometric data on analytes (1)–(4) at ng.(mL)-1 concentration levels in mixtures in solution obtained for positive operation mode. High accuracy static and molecular dynamic quantum chemical computations and chemometrics are also utilized. Experimental 3D structural parameters of steroids obtained for stochastic dynamic diffusion theory are correlated with available crystallographic data. [ABSTRACT FROM AUTHOR]

The study encompassed experimental mass spectrometric and theoretical quantum chemical studies on adsorption of uranium species in different oxidation states of the metal ion, and oxides of U x O y n+ type, where x = 1 or 3, y = 2 or 8, and n = 0, 1 or 2 onto nanosize-particles of saltrock oxides MO (M = MgII, CaII, NiII, CoII, SrII or BaII), M2O y (M = AuIII or AgI, y = 3 or 1) silicates 3Al2O3.2SiO2, natural kaolinite (Al2O2·2SiO2·2H2O), illite (K0.78Ca0.02Na0.02(Mg0.34Al1.69FeIII 0.02)[Si3.35Al0.65]O10(OH)2·nH2O), CaSiO3, 3MgO·4SiO2,H2O, and M1M2(SiO4)X2 (M1 = M2 = Al or M1 = K, M2 = Al, X = F or Cl), respectively. The UV-MALDI-Orbitrap mass spectrometry was utilized in solid-state and semi-liquid colloidal state, involving the laser ablation at λ ex = 337.2 nm. The theoretical modeling and experimental design was based on chemical-, physico-chemical, physical and biological processes involving uranium species under environmental conditions. Therefore, the results reported are crucial for quality control and monitoring programs for assessment of radionuclide migration. They impact significantly the methodology for evaluation of human health risk from radioactive contamination. The study has importance for understanding the coordination and red-ox chemistry of uranium compounds as well. Due to the double nature of uranium between rare element and superconductivity like materials as well as variety of oxidation states ∈ (+1)–(+6), the there remain challenging areas for theoretical and experimental research, which are of significant importance for management of nuclear fuel cycles and waste storage. [ABSTRACT FROM AUTHOR]

Bacteria predominantly use quorum sensing to regulate a plethora of physiological activities such as cell-cell crosstalk, mutualism, virulence, competence, biofilm formation, and antibiotic resistance. In this study, we investigated how certain potent endophytic bacteria harbored in Cannabis sativa L. plants use quorum quenching as an antivirulence strategy to disrupt the cell-to-cell quorum sensing signals in the biosensor strain, Chromobacterium violaceum. We used a combination of high-performance liquid chromatography high-resolution mass spectrometry (HPLC-ESI-HRMS) and matrix-assisted laser desorption ionization imaging high-resolution mass spectrometry (MALDI-imaging-HRMS) to first quantify and visualize the spatial distribution of the quorum sensing molecules in the biosensor strain, C. violaceum. We then showed, both quantitatively and visually in high spatial resolution, how selected endophytic bacteria of C. sativa can selectively and differentially quench the quorum sensing molecules of C. violaceum. This study provides fundamental insights into the antivirulence strategies used by endophytes in order to survive in their ecological niches. Such defense mechanisms are evolved in order to thwart the plethora of pathogens invading associated host plants in a manner that prevents the pathogens from developing resistance against the plant/endophyte bioactive secondary metabolites. This work also provides evidence towards utilizing endophytes as tools for biological control of bacterial phytopathogens. In continuation, such insights would even afford new concepts and strategies in the future for combating drug resistant bacteria by quorum-inhibiting clinical therapies. [ABSTRACT FROM AUTHOR]

The paper reports ultraviolet matrix-assisted laser desorption/ionization mass spectroscopy (UVMALDI-MS) protocol for determination of complex heterogeneous emulsion or suspension formulations. The active agents and surfactants are morpholine fungicide fenpropimorph ( 1), amorolfine ( 2), tridemorph (mixture of 2,6-dimethyl-4-alkylmorpholins 3-6), 2,6-dimethyl-4-[2-methyl-3-(6-methyl-decahydro-naphthalen-2-yl)-propyl]-morpholine (7), dodemorph ( 8), main metabolite of 1 fenpropimorph acid ( 9), sodium dodecyl sulfate ( 10), and stearate ( 11). The full method and techniques validation as well as method performance parameters are discussed in terms of their maximal representativeness toward real environmental and foodstuff assay problems. These are additionally complicated by heterogeneous laterally, vertically, and time distribution of pesticide contaminants and their major metabolites in environmental samples. The real environmental heterogeneous distribution is elucidated, studying sterilized soil fractions with particle size 2.0 μm, clay content 11.5 %, silt 23.0 %, sand 8.1 %, and pH ∈ 6.0-8.1. A statistical sampling cluster approach is used. The method performance parameters are concentration LODs of 0.026 mg kg (res. LOQs 0.08666 mg kg). Concentration linear dynamic ranges are ∈ 0.025-7.3 mg kg ( r = 0.99822 and 0.99421) and ∈ 2.3-7.4 mg kg (level of confidence of 99.33 %) for complex spiked heterogeneous soil samples. The data illustrates the great capability of method and its promising application for environmental contamination monitoring and controlling programs for assessment. [ABSTRACT FROM AUTHOR]

Abstract: Despite that among non-camptothecin natural products promising anticancer therapeutics are evodiamine derivatives, involved into mechanism of physiological function of topoisomerase-I. But, more recent findings have been shown that substituted quinazole alkaloids act as transient receptor potential vanilloid 1 agonists. The TRP(V1) is a calcium ion channel, activated by pH, heat and inflammatory activators. I is implicated in pain sensing. TRPV1 agonist is capsaicine (1). Both 1 and evodiamine (2), therefore, produce same physiological response, but are structurally unrelated from chemical viewpoint. Furthermore precise mechanistic aspects of drugs receptor interactions are still not fully understood. This study is the first one, which provides assessment of molecular factors contributing significantly to selectivity of 2 and rutaecarpine (3) as well as their twenty-two new functionalized derivatives towards (TRP)V1. The suggested new functionalization type of molecular skeleton, which is completely different one in respect the known derivatives, which is implicated in treatment of variety of cancer cell lines interacting preferably with topoisomerase-I. It resulted to increasing of the binding affinity and selectivity of the functionalized derivatives specifically to (TRP)V1∈1.36–1.72 and ∈2.50–3.16 higher than 1–3. [Copyright &y& Elsevier]

Highlights: [•] Mass spectrometry (ESI, APCI and MALDI), crystallography and quantum chemistry of cyclodextrins. [•] Macroscopic complex CDs/n stability (n ∈0–12): self-assembly of non-covalent bonding interactions. [•] Non-covalent interactions in CDs crystals and physical gas-phase phenomena. [ABSTRACT FROM AUTHOR]

Abstract: This study focused on the development of the accurate and precise quantitative method for the determination of pesticides bromacil (1), terbacil (2), lenacil (3), butafenacil (4) and flupropacil (5) in fruit based soft drinks. Three different types of drinks are bought from market; huddled orange fruit drink (100%) (I), red-oranges (II) and multivitamin drink containing strawberry, orange, banana and maracuja (III). Samples were analyzed “with” and “without” pulp utilizing LC–ESI (or APCI) MS/MS, HPLC–ESI–(or APCI)–MS/MS and UV-MALDI–Orbitrap-MS methods. The effect of high complexity of the food matrix on the analysis was discussed. Study focuses on the advantages of the UV-MALDI–Orbitrap-MS method compared to the traditionally involved GC alone or hybrid methods such as GC–MS and LC–MS/MS for quantification of pesticides in water and soft drinks. The developed method included the techniques performed for validation, calibration and standardization. The target pesticides are widely used for the treatment of citrus fruits and pineapples, but for soft drink products, there are still no clear regulations on pesticide residues limits. The matrix effects in the analysis of fruit drinks required implementation of the exact standard reference material corresponds to the variety of food matrices. This paper contributed to the broad analytical implementation of the UV-MALDI–Orbitrap-MS method in the quality control and assessment programs for monitoring of pesticide contamination in fruit based sodas. [Copyright &y& Elsevier]

The paper highlighted the molecular docking drug design and analysis of eighteen 1-18 substituted benzo[ i]phenanthridines as promising non-camptothecin topoisomerase-I-targeting agents for anticancer therapeutics. Although antitumor camptothecin-based drugs such as topotecan and irinotecan are successfully implemented into clinical practice, prevent their lower solubility CPTs the widespread clinical use of naturally occurring products of the same class. Synthetic chemicals that have benzo[ i]phenanthridine core to be an active as antitumor Top-I-therapeutics in vivo. Therefore, the search for new effective drugs with the same molecular framework is a successful strategy of the state of exception that is of great interest to the border, the anticancer drug research. Therefore, the Top-I/drugs docking analysis is compared to Top-I/topotecan data. All substances 1- 18 had higher binding affinity and thermodynamic stability (Δ G ∈ (−16.59) − (−64.08) kcal mol). Top-I/topotecan complex showed positive Δ G = 30.21 kcal mol value. In the series of successfully isolated fifteen derivatives, most promising for in vivo assay is 17 (Δ G = −57.95 kcal mol), issuing a dipole moment (μ) of 11.1007 Debye. The value is different of Δ μ = |2.6859| Debye, than the topotecan ( μ = 8.4148 Debye) one. Thus, the higher solubility of 17 is under physiological conditions. The 16 and 18 have higher dipole moments Δ μ of |2.2528| and |2.6023| Debye than topotecan. The Δ G = −16.59 and −20.51, kcal mol values are lower than 17. However, since the quantities remain negative, the substances would also be promising therapeutic candidates. The 6 revealed the lowest Δ G (−64.08 kcal mol) but μ of 3.8204 Debye. The simple synthetic roads, which are produced the substances ∈ 47.3-73.6 % yields are additional benefits for the potential pharmaceutical industrial manufacturing. The mechanistic aspects of the photo- and thermal cyclization processes greatly affect the products are evaluated by theoretical quantum chemical methods for first time. The mass spectrometric data obtained from different ionization stresses because the method provided highly accurate structural information on analyte fg g concentrations and direct imaging bioassay. For this reason, the molecular fragmentation of the isolated derivatives is a comprehensively debate. [ABSTRACT FROM AUTHOR]

Highlights: [•] ESI-MS/MS and quantum chemical study of SnIVCl4 catalyzing coupling reaction of benzaldehydes. [•] Redox SnIV/SnII catalyzing process explaining the complex MS fragmentation scheme of the products. [•] Binuclear SnII-organometallic precursor with thermodynamics ΔG =−52996.80kcal/mol. [•] Mechanistic aspects of the coupling process, improving significantly the reaction effectiveness. [ABSTRACT FROM AUTHOR]

Abstract: The paper highlighted the capability of the UV-MALDI mass spectrometry, employing the Orbitrap analyzer for solid-state assay of halogenated phenyl–pesticides in mixtures. It is successfully applied for the analysis of eighteen (1)–(18) molecular objects of Fenarimol (1) type and their condensation products (P5)–(P12). The full method and technique validation is performed using the dried droplet sample preparation technique on embedded analytes in novel organic matrix crystals of N-(1H-benzoimidazol-2-yl)-guanidine (M4) and (E)-phenyl-2-pyridyl ketone oxime (M5), resulting to successful ionization of the analytes. Since the sampling technique in the UV-MALDI method is a key step in the overall process impacting significantly the metrology through the reproducibility of the data, the crystallization of M4, M5 and matrix–analyte in situ morphology of the samples is controlled by single crystal X-ray diffraction. The achieved promising metrology of LODs, of 0.46ngkg−1 (1.53ngkg−1 LOQs), is several orders of magnitude lower than the reported ecotoxicological effect values of studied pesticides. It is confirmed by the partial validated protocol based on ESI-MS. Inasmuch that LC-MS/MS is a method of choice for foodstuffs monitoring of organic contaminations, due to its routine quantitative analytical procedures, it is often characterized with the difficulties of the chromatographic separation of the closely structured analytes at a large scale of experimental conditions, complex multi-step sampling pretreatments, which inevitably alert the variables through the systematic and random errors. In this respect, notwithstanding the complex quantitative UV-MALDI-Orbitrap-MS procedure, conceptually different from the LC-MS/MS one, its high resolving power, capability for achieving meaningful analytical qualitative, quantitative and structural information of low-molecular weight analytes, its instrumental and sampling operation flexibility, applicable for a large scale of foodstuff matrices, and operating at the analyte concentrations of up to fgg−1 make UV-MALDI-Orbitrap-MS a perspective method of choice for an extensive implementation in the foodstuffs monitoring practice for control of the most essential task related to the assessment of the human health risks from environmental and foodstuff contaminations. [Copyright &y& Elsevier]

Abstract: The paper studied factors of the gas phase (GP) ionic stabilization of molecular organic crystals of salts. The single crystal X-ray diffraction, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) methods are employed. The GP phenomena are explained by the comprehensive quantum-chemical theoretical models, providing significant information for the electronic structures and thermodynamics of the observed MS species. The n-chloro-alkyl aliphatic heterocyclic 5-sulfosalicylates i.e. 1-(2-chloroethyl) pyrrolidinium 5-sulfosalicylicilate (1), 1-(2-chloroethyl)-piperidinium 5-sulfosalicylicilate (2), and 1-(3-chloropropyl) piperidinium 5-sulfosalicylicilate (3) are examined. The ionic systems that contain N+H-heterocyclic fragments, a complex MS image variety of monocations, quaternary ammonium dications and hydrogen bonded molecular complexes revealed. Their stabilization is explained by proton transfer (PT), charge-transfer (CT) and Jahn–Teller (JT) effects. The 4-(2-chloroethyl) morpholinium hydrochloride crystals (4) yielded quaternary ammonium adduct which structure is crystallographically determined. In parallel the GP stabilized ions of 4 are analyzed. The complementary application of the single-crystal X-ray diffraction and MS methods provided unique structural evidences in condenses and in the GP able to understand the competitive intramolecular and environmental factors contributing to the thermodynamics stability of the ionic species. Therefore, the data reported are helped for more comprehensive knowledge of the basic mass spectrometric GP and phase transition phenomena with both its methodological development and used robust analytical technique application. [Copyright &y& Elsevier]

Abstract: The paper presented a comprehensive theoretical and experimental study on the molecular drugs-design, synthesis, isolation, physical spectroscopic and mass spectrometric elucidation of novel functionalization derivatives of Cytisine (Cyt), using nucleosidic residues. Since these alkaloids have established biochemical profile, related the binding affinity of the nicotinic acetylcholine receptors (nAChRs), particularly α7 sub-type, the presented correlation between the molecular structure and properties allowed to evaluated the highlights of the biochemical hypothesises related the Schizophrenia. The anticancer activity of α7 subtype agonists and the crucial role of the nucleoside-based medications in the cancer therapy provided opportunity for further study on the biochemical relationship between Schizophrenia and few kinds of cancers, which has been hypothesized recently. The physical electronic absorptions (EAs), circular dichroic (CD) and Raman spectroscopic (RS) properties as well as mass spectrometric (MS) data, obtained using electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) methods under the positive single (MS) and tandem (MS/MS) modes of operation are discussed. Taking into account reports on a fatal intoxication of Cyt, the presented data would be of interest in the field of forensic chemistry, through development of highly selective and sensitive analytical protocols. Quantum chemical method is used to predict the physical properties of the isolated alkaloids, their affinity to the receptor loop and gas-phase stabilized species, observed mass spectrometrically. [Copyright &y& Elsevier]

Background: The aim of this study was to evaluate the antimicrobial activity and the cytotoxicity of the ethanol crude extract, fractions and isolated compounds from the twigs of Eriosema robustum, a plant used for the treatment of coughs and skin diseases. Methods: Column chromatographic and spectroscopic techniques were used to isolate and identify eight compounds, robusflavones A (1) and B (2), orostachyscerebroside A (3), stigmasterol (4), 1-O-heptatriacontanoyl glycerol (5), eicosanoic acid (6), 3-O-β-D-glucopyranoside of sitosterol (7) and 6-prenylpinocembrin (8), from E. robustum. A two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against fungi and bacteria, and the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay was used to evaluate the cytotoxicity. Results: Fraction B had significant antimicrobial activity against Aspergillus fumigatus and Cryptoccocus neoformans (MIC 0.08 mg/ml), whilst the crude extract and fraction A had moderate activity against A. fumigatus and Candida albicans (MIC 0.16 mg/ml). Fraction A however had excellent activity against Staphylococcus aureus (MIC 0.02 mg/ml), Enterococcus faecalis and Escherichia coli (MIC 0.04 mg/ml). The crude extract had significant activity against S. aureus, E. faecalis and E. coli. Fraction B had good activity against E. faecalis and E. coli (MIC 0.08 mg/ml). All the isolated compounds had a relatively weak antimicrobial activity. An MIC of 65 μg/ml was obtained with robusflavones A (1) and B (2) against C. albicans and A. fumigatus, orostachyscerebroside A (3) against A. fumigatus, and robusflavone B (2) against C. neoformans. Compound 8 had the best activity against bacteria (average MIC 55 μg/ml). The 3 fractions and isolated compounds had LC50 values between 13.20 to > 100 μg/ml against Vero cells yielding selectivity indices between 0.01 and 1.58. Conclusion: The isolated compounds generally had a much lower activity than expected based on the activity of the fractions from which they were isolated. This may be the result of synergism between different compounds in the complex extracts or fractions. The results support the traditional use of E. robustum to treat infections. The crude extract had a good activity and low preparation cost, and may be useful in topical applications to combat microbial infections. [ABSTRACT FROM AUTHOR]

Abstract: The relationship between the molecular structure and physical properties of functionalized naturally occurred Ergot-alkaloids as potential dopamine D3 receptor agonists is presented. The molecular modeling of the ergoline-skeleton is based on the comprehensive theoretical study of the binding affinity of the isolated chemicals towards the active sites of the D3 sub-type receptor (D3R) loops. The studied proton accepting ability under physiological conditions allows classifying four types of monocationics, characterizing with the different binding modes to D3R involving selected amino acid residues to the active sites. These results marked the pharmaceutical potential and clinical usage of the reported compounds as antipsychotic drugs for Schizophrenia treatment, since they allowed evaluating the highlights of the different hypothesizes of the biochemical causes the illness. The applied complex approach for theoretical and experimental elucidation, including quantum chemistry method, electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) mass spectrometric (MS) methods, nuclear magnetic resonance and vibrational IR and Raman spectroscopy on the isolated fifteen novel derivatives (1)–(15) and their different protonated forms (1a)–(15a) evidenced a strong dependence of molecular conformation, physical properties and binding affinity. Thus, the semi-synthetic functionalization of the naturally occurred products (NPs), provided significant possibilities to further molecular drugs-design and development of novel derivatives with wanted biological function, using the established profile of selected classes/families of NPs. The work described chiefly the non-linear (NL) approach for the interpretation of the mass chromatograms on the performed hybrid high performance liquid chromatography (HPLC) tandem MS/MS and MS/MS/MS experiments, discussing the merits and great diversity of instrumentation flexibility, thus achieving fundamental structural information, indispensable for the analysis of Ergot-alkaloid derivatives, which under the physiological conditions easily converted to d-lysergic acid (LSD). [Copyright &y& Elsevier]