Determination of Aroma Compounds from Alcoholic Beverages in Spiked Blood Samples by Means of Dynamic Headspace GC–MS

Some aroma compounds found in alcoholic beverages are characteristic of a certain beverage (i.e. 2,4-decadienoic acid ethyl ester is characteristic of pear spirit and 5-butyltetrahydro-4-methylfuran-2-on “whiskey lactone” is characteristic of aged spirits like whiskey). These substances were detectable in beverages but not in blood samples. The aim of this investigation was to find a sensitive sampling technique for aroma compounds in whole blood samples. This technique may be used in forensic toxicology for examination of drinking claims. The method comprises dynamic headspace sampling using a purge and trap concentrator, followed by quantitative gas chromatography–mass spectrometry (dynamic HS–GC–MS). The influence of sample preparation, trap adsorbents and sample temperature as well as desorption time and purge time on the quality of the analytical results were investigated. The following optimal parameters were determined: stirred and diluted whole blood sample without salt addition, use of Carbotrap C as trap material, sample temperature at 80 °C, desorption time 20 min and purge time 30 min. These optimal parameters were used for the determination of detection limits (LOD). The LOD of aroma compounds by means of dynamic headspace sampling were compared with the results of conventional sampling: the static headspace technique. Limits of detection for the aroma compounds with conventional static headspace GC are in the range 400–10,000 μg L^?1. Dynamic headspace–GC was found to be a more sensitive sampling technique for most of the aroma compounds investigated (e.g. C₄–C₈ ethyl esters, benzoic acid ethyl ester, linalool oxide and 4-ethylguaiacol) with detection limits between 1 and 50 μg L^?1, but there were also limits to the sampling of substances with lower volatility like decanoic acid ethyl ester, 2,4-decadienoic acid ethyl ester, eugenol and whiskey lactone with detection limits of about 1,000 μg L^?1.     

Nanotubes fabricated from Ni-naphthalocyanine by a template method

Novel naphthalocyanine (Nc) nanotubes with special wall structures were fabricated by a template method using Nc molecules as building blocks. Thermal stabilization of the ordered columnar structures of the tetrakis(tert-butyl)naphthalocyanine (Ni-BNc) molecules, induced from the pi-pi interactions in the nanoscale channels of an alumina template, resulted in Nc nanotubes with walls consisting of well-ordered Nc molecular disks. Further thermal treatment of Ni-BNc at 600 degrees C produced carbonized Nc nanotubes containing ordered columnar, graphitic wall structures with the graphene disks arranged perpendicular to the tube axis. These nanotubes may be useful for extending the application of Nc molecules for nanodevice fabrication.     

CrIII-Phthalocyaninate: Darstellung,Eigenschaften und Kristallstruktur von l-Bis(triphenylphosphin)iminium-trans-di(nitrito(O))phthalocyaninato(2–)-chromat(III)

Cr^III Phthalocyaninates: Synthesis, Properties, and Crystal Structure of l-Bis(triphenylphosphine)iminium trans-Di(nitrito(O))phthalocyaninato(2–)chromate(III) [Cr(H₂O)₂Pc^2?]I_x reacts with excess (PNP)NO₂ in dimethylformamide to yield less soluble greenblack l-bis(triphenylphosphine)iminium trans-di(nitrito(O))phthalocyaninato(2–)chromate(III), ^l(PNP)^trans[Cr(ONO)₂Pc^2?], which crystallizes in the triclinic space group P1 (No. 2) with Z = 2. The Cr atom is in the center of the Pc^2? ligand and the two nitrite ions are monodentate O-coordinated in a mutually trans arrangement to the Cr atom. The Cr? O and Cr? N_iso bond distances are 1.9898(14) und 1.981(2) Å, respectively. The geometric data of the coordinated nitrite ion are: d(N? O) = 1.307(2) Å; d(N? O) = 1.205(2) Å; ?(O? N? O) = 113.7(2)°; ?(Cr? O? N) = 116.85(12)°. The non-bonding O atoms are trans to the Cr atom. The Pc^2? ligand is slightly saddled. Three weak spin-allowed trip-quartet(TQ) transitions (in 10³ cm^?1): TQ1 (8.20) < TQ2 (11.3) < TQ3 (20.33) and the characteristic π-π* transitions of the Pc^2? ligand: B (14.68) < Q₁ (27.1) < Q₂ (29.0) < N (35.4) are observed in the UV-VIS-NIR spectrum. Prominent luminescence spectra are obtained by excitation within the TQ1 region, in which the spin-forbidden trip-sextet transition at 7376 cm^?1 dominates at low temperatures (T < 50 K). The vibrational spectra are discussed. In coincidence of the excitation lines with TQ3, v_s(Cr? O) at 378 cm^?1 is selectively resonance Raman (RR) enhanced. v_as(Cr? O) is observed in the FIR spectrum at 391 cm^?1. The following internal vibrations (in cm^?1) of the nitrito ligand are in the MIR spectrum: v_as(N? O)/1447 > v_as(N? O)/1018/1029 > δ(O? N? O)/828 and in the RR-spectrum: v_s(N? O)/1410 > v_s(N? O)/952, the last followed by three overtones.     

Sequencing and four-state minisatellite variant repeat mapping of the D1S7 locus (MS1) by fluorescence detection

Minisatellite variant repeat mapping by polymerase chain reaction (MVR-PCR) reveals an enormous degree of variation in the human minisatellite regions. The original approach involved the use of 32P-labelled probes to detect the MVR-PCR products generated. To date, the loci mapped include D1S8, D7S21 and D16S309. However, the most polymorphic locus, D1S7 (MS1), which has been used in forensic analysis, has presented technical difficulties, initially due to its short 9 bp repeats that are much shorter than any conventional primer sequences. This was overcome by using the method of "wrapping around" primers employing inosine at the redundancy position. The difficulty of cloning highly repetitive DNA was overcome by utilising specialised competent SURE cells. We report the cloning and sequencing of selected short MS1 alleles to determine the variety of repeat types. This survey revealed nine types, four of which represented greater than 80% of the sequenced repeats. The reported MVR-PCR system maps the MS1 locus for these four common repeat types by fluorescence detection.     

Gas-Phase cationization and protonation of neutrals generated by matrix-assisted laser desorption

The ionization mechanisms involved in matrix-assisted ultraviolet laser desorption/ionization (MALDI) were studied with a time-of-flight mass spectrometer. When protonated or cationized quasimolecular ions generated by MALDI are not extracted promptly, their abundance is a function of the delay time between laser irradiation and ion extraction, maximizing at an optimum delay time (DTM) of a few hundred nanoseconds. The ion abundance at DTM exceeds that of prompt extraction by a factor of 2 or more. Increasing the cation density near the sample surface reduces the DTM, whereas increasing the desorption laser irradiance has the opposite effect. The enhancement suggests extensive gas-phase ion-molecule reactions after irradiation by the desorption laser has ceased.     

Syntheses and Structure of Gd<Subscript>3</Subscript>Rh<Subscript>1.940(7)</Subscript>In<Subscript>4</Subscript>

Summary. The gadolinium–rhodium–indide Gd₃Rh_1.940(7)In₄ was prepared by arc-melting of the elements and subsequent annealing in a corundum crucible in a sealed silica tube. Gd₃Rh_1.940(7)In₄ adopts the hexagonal Lu₃Co_1.87In₄ type, space group , a = 781.4(5), c = 383.8(3) pm, wR2 = 0.0285, BASF = 0.375(1) (merohedric twinning via a twofold axis (xx0)), 648 F² values, 22 variables. The structure is derived from the well known ZrNiAl type through an ordering of rhodium and indium atoms on the Ni2 sites. The Rh/In ordering forces a reduction of the space group symmetry from to , leading to merohedric twinning for the investigated crystal. The Rh1 site has an occupancy of only 94.0(7)%. The investigated crystal had a composition Gd₃Rh_1.940(7)In₄. The main geometrical motif are three types of centered, tricapped trigonal prisms, i.e., [Rh1In2₆Gd₃], [Rh2Gd₆In2₃], and [In1Gd₆In2₃]. The shortest interatomic distances occur for Rh–In (276–296 pm) followed by In–In (297 pm). Together, the rhodium and indium atoms build up a three-dimensional [Rh_1.940(7)In₄] network, in which the gadolinium atoms fill slightly distorted pentagonal channels. The crystal chemistry of Gd₃Rh_1.940(7)In₄ is discussed on the basis of a group-subgroup scheme.     

A one dimensional microscopical model for the study of the coherence in the stopping power problem. Part 3

We consider the quantum mechanical problem of a particle being scattered inelastically by a chain ofN infinitely heavy, equidistantly spaced two-level atoms. In a previous paper (Süßmann, G., Szilas, P.: Z. Phys. B — Condensed Matter42, 253 (1981)) the time dependent problem of a Gaussian wave packet impinging on the target atoms has been studied and an explicit asymptotic expression for the reduced density matrix ρ _R of the particle has been given. We now introduce the coarse grained density matrix \(\bar \rho _R\) . The incoherenceI?1-Tr( \(\bar \rho _R^2\) ), i.e. the deviation of the state of the particle from a pure state, being small on certain conditions, we find a single particle wave function ψ with \(\psi (x',t)\psi ^* (x'',t) \approx \left\langle {x'\left| {\bar \rho _R (t)} \right|x''} \right\rangle\) and a nonlinear Hermitean HamiltonianH _ψ=p ²/2m+W _ψ such thati?ψ(x, t)=H _ψψ(x, t) describes the time evolution. Finally we also considerW _ψ within the framework of the phenomenological theory of nonlinear frictional operators.     

Facile synthesis and characterization of monocrystalline cubic ZrO2 nanoparticles

Crystalline ZrO₂ nanoparticles were prepared from zirconium isopropoxide by slow hydrolysis and subsequent hydrothermal treatment of solutions containing various amounts of sodium hydroxide at 180 °C. Whereas moderately basic solutions lead to the formation of nanoparticles of monoclinic ZrO₂ with plate-like morphology, and nanoparticles of the cubic ZrO₂ high-temperature polymorph with diameters of approx. 5 nm were obtained from strongly basic solutions. The morphology, structure and properties of as-synthesized nanoparticles were characterized using HRTEM, XRD, Raman spectroscopy, UV–vis, PL spectroscopy and BET measurements. The formation of both, the monoclinic and the cubic polymorph, was confirmed by electron microscopy and Raman spectroscopy. The crystallinity and morphology of the resulting ZrO₂ nanoparticles can be adjusted by the choice of the reaction conditions. The cubic ZrO₂ nanoparticles have a high surface area (300 m²/g) and exhibit a strong photoluminescence in the UV region.     

Relative quantification of erythropoietin receptor-dependent phosphoproteins using in-gel 18O-labeling and tandem mass spectrometry

On examining different proteomics approaches for the investigation of structure-function relationships of erythropoietin (EPO) receptor signaling, it was found that two-dimensional gel electrophoresis/mass spectrometry procedures are clearly limited in their ability to detect low-expressed signaling proteins. Instead it was found that a strategy involving anti-phosphotyrosine immunoprecipitation, one-dimensional gel electrophoresis (1DE), and capillary liquid chromatography/tandem mass spectrometry (LC/MS/MS) provides the sensitivity required for identification of signaling proteins. In the present work the immunoprecipitation/1DE/LC/MS approach was combined with an in-gel 18O-labeling technique to analyze EPO receptor-dependent proteins. Identification and relative quantification of more than 180 EPO receptor-dependent proteins were achieved directly based on the in-gel 18O-labeling approach.     

Standardisierung der dünnschichtchromatographischen Trennungen von Flechtensäuren zur Chemotaxonomie von Flechten

Zusammenfassung Die dünnschichtchromatographische Trennung von Flechtenextrakten zur Unterstützung der Taxonomie wurde in Bezug auf die Trennleistung und auf die Reproduzierbarkeit optimiert. Dabei wurden besonders gute Trennleistungen erhalten mit dem Flie?mittelgemisch Benzol:Dioxa:Eisessig=90∶25∶4 bei Verwendung von Kieselgel, dessen Aktivit?t durch eine Umgebung mit relativer Feuchte von 70% festgelegt wurde, und mit Methylenchlorid als Eluiermittel bei Verwendung von mit Oxals?ure impr?gniertem Kieselgel und antiparallelem Aktivit?tsgradienten. Eine hohe Reproduzierbarkeit der Trennungen wurde erreicht durch Verwendung der Vario-KS-Kammer nach Geiss, die die Einstellung einer definierten Schichtaktivit?t bzw. eines definierten Aktivit?tsgradienten und eine reproduzierbare Vorbedampfung der Schicht mit Flie?mittel erm?glicht. Es konnte gezeigt werden, da? durch unterschiedliche chromatographische Trennungen der gleichen Extrakte und durch die Verwendung verschiedener Anf?rbereagenzien die Identifizierung und damit die Aussagekraft für taxonomische Probleme steigt.

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Standardisation of the thin-layer chromatographic separation of lichen acids for the chemotaxonomy of lichens

Summary The thin-layer chromatography of lichen extracts for taxonomic studies has been optimized in relation to separation and to reproducibility. Especially good separations were found with benzene:dioxane:acetic acid (90∶25∶4) developer and silica gel thin-layer plates, whose activity was fixed by an ambient moisture content of 70%, and with methylene chloride developer and silica gel plates impregnated with oxalic acid and antiparallel activity gradient. High reproducibility of separation was obtained using the Geiss Vario-KS tank, which allows the activity of the plates or the activity gradient to be adjusted and which also allows reproducible exposure of plates to the vapour of developing solvents. By different chromatographic separations of the same extracts and by using different colour reactions the accuracy of identification for taxonomic studies has been improved.