Trace elemental analysis of automotive paints by laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS)

Paints and coatings are frequently encountered as types of materials that are submitted to forensic science laboratories as a result of trace evidence transfers. The aim of this study was to develop a method to complement the commonly used techniques in a forensic laboratory in order to better characterize these samples for forensic purposes. A laser ablation method has been used to simultaneously sample several layers directly prior to introduction into an inductively coupled plasma-mass spectrometer for the detection and quantification of the trace metals present in the layer(s). Time-resolved analysis plots displaying the elemental response and quantification of selected metals are compared to associate/discriminate paint samples. Matrix-matched standards were successfully incorporated into the analysis scheme for quantification of lead in the solid paint samples. Preparation of new matrix-matched standards for quantification of additional elements developed for this study are also presented. A sample set of eighteen (18) survey automotive paint samples have been analyzed with the developed method in order to determine the utility of LA-ICP-MS for trace element analysis of paints.     

Biooxidation of (+)-catechin and (-)-epicatechin into 3,4-dihydroxyflavan derivatives by the endophytic fungus Diaporthe sp. isolated from a tea plant

The microbial transformation of (+)-catechin (1) and (-)-epicatechin (2) by endophytic fungi isolated from a tea plant was investigated. It was found that the endophytic filamentous fungus Diaporthe sp. transformed them (1, 2) into the 3,4-cis-dihydroxyflavan derivatives, (+)-(2R,3S,4S)-3,4,5,7,3',4'-hexahydroxyflavan (3) and (-)-(2R,3R,4R)-3,4,5,7,3',4'-hexahydroxyflavan (7), respectively, whereas (-)-catechin (ent-1) and (+)-epicatechin (ent-2) with a 2S-phenyl group resisted the biooxidation.     

Poly(arylene ether)s with pendant diphenyl phosphoryl groups: Synthesis,characterization, and thermal properties

A series of poly(arylene ether)s, (PAEs), carrying a pendant diphenyl phosphoryl group were prepared via the nucleophilic aromatic substitution (NAS) reactions of 3,5‐difluorotriphenylphosphine oxide, 6 . The difluoro monomer 6 was synthesized via two‐step reaction sequence and subsequently characterized by ¹H, ¹³C, ¹⁹F, and ³¹P NMR spectroscopy, GC/MS, and elemental analysis. The reactivity of the electrophilic sites in 6 , activated by only a diphenylphosphoryl group located in the meta‐position, in 6 was probed via NMR spectroscopy and model reactions and was determined to be sufficient to undergo typical NAS reactions. High molecular weight, amorphous, organic soluble poly(arylene ether)s, bearing a pendant diphenylphosphoryl group, were prepared via the reaction of 6 with a variety of bis‐phenols under typical NAS conditions. The poly(arylene ether)s were characterized for structure via the use of ¹H, ¹³C, and ³¹P NMR spectroscopy while their thermal properties were evaluated using DSC and TGA analysis. The glass transition temperatures (T_g) of the synthesized PAEs ranged from 143 to 175 °C, while their 5% weight loss temperatures ranged from 467 to 510 °C under nitrogen and from 470 to 526 °C in air. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Generating functional for mesonic ChPT with virtual photons in a general covariant gauge

The European Physical Journal A - The divergent part of the one-loop effective action in Chiral Perturbation Theory with virtual photons has been evaluated in an arbitrary covariant gauge. The...     

LETTER TO THE EDITOR: General-Relativistic Model of Magnetically Driven Jet

The general scheme for the construction of the general-relativistic model of the magnetically driven jet is suggested. The method is based on the usage of the 3 + 1 MHD formalism. It is shown that the critical points of the flow and the explicit radial behavior of the physical variables may be derived through the jet profile function.     

Bisanthraquinone metabolites produced by the endophytic fungus Diaporthe sp

Two bisanthraquinones named (+)-epicytoskyrin (1) and (+)-1,1'-bislunatin (2) were produced by the endophytic fungus from a tea plant, which is a species closely related to Diaporthe phaseolorum strain sw-93-13. The chemical structures of the metabolites were elucidated on the basis of the physicochemical properties including the circular dichroism (CD) spectrum.     

Ruthenium complexes of the general formula [RuCl2(PHOX)2] and their catalytic activity in the Mukaiyama aldol reaction

New ruthenium phosphinooxazoline (PHOX) complexes were synthesized and applied in the Mukaiyama aldol reaction. Four ruthenium complexes of the general formula [RuCl₂(PHOX)₂] were synthesized from [RuCl₂(dmso)₄] and the corresponding PHOX ligands through thermal ligand exchange. Two of the complexes were characterized structurally. Achiral PHOX ligands gave the ruthenium complexes as single isomers, whereas chiral PHOX ligands gave a mixture of isomers and also some incomplete substitution. After activation by chloride abstraction, one of the new ruthenium complexes was applied as catalyst in the Mukaiyama aldol reaction to give silyl-protected β-hydroxyl alcohols in 74–92% isolated yields (room temperature, 18–24 h reaction time, 1 mol % catalyst loading).