On the perspectives of capillary electrophoresis modes for the determination of morphine in human plasma without sample pretreatment

Screening and confirmation of drugs of abuse in body fluids are important for the medicinal treatment and form the legal basis of court judgments. A fast and precise identification of toxic substances is necessary. Morphine was determined in human plasma by capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) using sample stacking mode. The electrophoretic separation was performed in an uncoated fused-silica capillary, 70 cm long to the detector, with an additional 10 cm to the cathode (75 microm i.d. and 360 microm o.d.). The UV absorbance detection was set at 190 nm. The electrophoretic buffers were prepared from 60 to 300 mm disodium tetraborate decahydrate, pH 10.5. Sodium dodecyl sulfate was added to the final solution in a concentration of 60 mm for MECC. All electrophoretic separations were carried out at 10 kV and the capillary temperature was ambient (25 degrees C). A linear calibration graph was obtained in the concentration range studied (50-5000 ng/mL). Several samples of drug-free plasma were checked for potential endogenous interference and the results showed no interference from the endogenous components, which co-migrated with morphine. As little as 50 ng/mL of morphine could be successfully analyzed by MECC in the concentration mode with acceptable precision. It is possible to determine morphine directly in plasma at therapeutic concentrations.     

Reactions of N,N-Disubstituted 5-Arylmethylidene-2-amino-thiazol-4(5H)-ones with CH Acids

Summary.  N,N-Disubstituted 5-arylmethylidene-2-aminothiazol-4(5H)-ones reacted with diethyl malonate, ethyl benzoylacetate, acetylacetone, or cyclopentadiene in refluxing toluene and in presence of powdered sodium to give the respective 5-arylmethylidene-2′-amino-2,5′-bithiazolylidene-4,4′-dione derivatives in moderate yields. 5-Benzylidene-2-morpholin-4-yl-2-thiazol-4(5H)-one reacted with malononitrile in toluene and in presence of powdered sodium under mild conditions to afford the 1:1 adduct, benzylmalononitrile, and 2-morpholin-4-yl-2-thiazol-4(5H)-one. However, similar treatment of 5-(4-methoxyphenylmethylidene)-2-morpholin-4-yl-2-thiazol-4(5H)-one with malononitrile yielded the 2,5′-bithiazolylidene-4,4′-dione derivative together with 4-methoxyphenylmethylidene malononitrile. Treatment of 5-benzylidene- and 5-(4-methoxyphenylmethylidene)-2-morpholin-4-yl-2-thiazol-4(5H)-ones with 3-phenyl-4-oxo-2-thioxo-1,3-thiazolidine in refluxing toluene and in presence of powdered sodium produced 5-arylmethylidene-3-phenyl-4-oxo-2-thioxo-1,3-thiazolidines in good yields. The structures of all products were deduced from microanalytical and spectroscopic data, mechanistic details are discussed. Corresponding author. E-mail: kamalkandeel@hotmail.com Received November 5, 2001. Accepted (revised) December 17, 2001     

Synthesis of block cotelomers involving a perfluorinated chain and a hydrophilic chain. III. Synthesis and use of fluorinated telogens with a trichloromethyl end group

The addition by redox catalysis (CuCl or FeCl₃ with benzoin) of CCl₄ and CCl₃? CF₂? CCl₃ on pentafluorostyrene and on fluorinated allyl ether, C₆F₁₃? C₂H₄? O? CH₂? CH?CH₂ was performed. The monoaddition compounds were mainly obtained with satisfactory yields and characterized by NMR (¹³C, ¹H, and ¹⁹F). These compounds were then used as telogens in telomerization by redox catalysis of acrylamide, methyl methacrylate, and acrylic acid and in radical-initiated telomerization of N-vinyl-pyrrolidone. The chain lengths of the hydrocarbonated sequences were determined from fluorine elemental analysis. A critical investigation of correlations between DP _n and concentrations of products involved was made.     

Synthesis of pyrazolo[4,3-d]oxazoles

1-Phenyl-3-methyl-5-pyrazolone-4-oxime reacted with benzylamine, methylamine, methyl- and ethyl ioides to give 3-methyl-1,5-diphenyl-1H-, 3-methyl-1-phenyl-1H- and 3,5-dimethyl-1-phenyl-1H-pyrazolo[4,3-d]oxazoles I, II. The structure of I was elucidated authentically through other routes by interaction of 1-phenyl-3-methyl-4,5-dioxopyrazolone with benzylamine and/or benzaldehyde and ammonium acetate. Various 3-meth-yl-5-aryl-1-phenyl-1H-pyrazolo[4,3-d]oxazoles IV were synthesized by the reaction of 4,5-dioxopyrazolone with aromatic aldehydes in the presence of ammonium acetate. Also, the structure of I was elucidated authentically via other routes by the reaction of 1-phenyl-3-methyl-4-imino-5-pyrazolone with each of benzylcyanide, benzylamine, benzaldehyde and benzalaniline.     

Ultradeep Hydrodesulfurization of Dibenzothiophene (DBT) Derivatives over Mo-Sulfide Catalysts Supported on TiO2-Coated Alumina Composite

The present paper reviews in detail the different studies now being conducted by our research team concerning the ultradeep hydrodesulfurization (HDS) of dibenzothiophene (DBT) derivatives over Mo/TiO₂ and Mo/TiO₂–Al₂O₃ catalysts. First, a detailed characterization of Mo/TiO₂ (P-25 Degussa, 50 m²/g) catalysts prepared by equilibrium adsorption technique shows that Mo- species are highly and uniformly dispersed on the surface of titania up to 6.6 wt% MoO₃ loading. Above this value, some aggregation of Mo occurs, leading to the formation of bulk MoO₃. Below 6.6 wt% MoO₃ loading, the Raman spectroscopy data of the calcined samples show that the supported Mo-species possess a highly distorted octahedral MoO₆ structure. TiO₂–Al₂O₃ composites were prepared by chemical vapor deposition (CVD) using TiCl₄ as a precursor. Using several characterization techniques, we demonstrated that the support composite presents a high dispersion of TiO₂ over -Al₂O₃ without forming precipitates up to ca. 11 wt% loading. Moreover, the textural properties of the composite support are comparable to those of alumina. Under the present sulfidation conditions (673 K, 5%H₂S/95%H₂), Mo-species supported on TiO₂ are better sulfided than on alumina, as demonstrated using XPS. This can be attributed to the relatively lower interaction between Mo-species and titania. The state of sulfide species supported on the composite support can be considered as a transition state between TiO₂ and Al₂O₃. However, at relatively higher TiO₂ loadings (ca. 11 wt%), Mo/TiO₂–Al₂O₃ catalysts exhibit sulfidability similar to that of Mo/TiO₂. The HDS tests conducted in both the laboratory and in industry show that sulfide catalysts supported on TiO₂–Al₂O₃ (ca. 11 wt% TiO₂) are more active than those supported on TiO₂ or Al₂O₃.     

One pot diastereoselective synthesis of new chiral spiro‐1,3,4‐thiadiazoles and 1,4,2‐oxathiazoles from (1R)‐thiocamphor

Herein we report an efficient one pot synthesis of new chiral 4,5‐dihydro‐4‐arylspiro[1,3,4‐thiadiazole]‐5,2′‐camphane‐2‐carboxylic acid ethyl esters 5–7 and 4,5‐dihydro‐3‐arylspiro[1,4,2‐oxathiazole]‐5,2′‐camphane 11–13 , using 1,3‐dipolar cycloaddition of nitrilimines 2–4 and nitrile oxides 8–10 to (1R)‐thiocamphor 1 respectively. The structure of the newly prepared 1,3,4‐thiadiazoles 5–7 (obtained as pure diastereoisomers) were fully established via spectroscopic analysis and X‐ray structural analysis which proved the absolute configuration of the C5 spiranic carbon to be (R). NMR spectral analysis were also very useful to show the new 1,4,2‐oxathiazoles 11–13 are mixtures of two (5R)/(5S) diastereoisomers with the ratio 6:4,7:3 and 6:4 respectively.     

Evaluation of copper Chemical-Vapor-Deposition films on glass and Si(100) substrates

Thin films of pure copper have been deposited on glass and Si(100) substrates using copper acetylacetonate [Cu(acac)₂] and copper HexaFluoroAcetylacetonate [Cu(HFA)₂] sources. A thermal, cold-wall, reduced pressure (3325–5985 Pa) Metal-Organic Chemical Vapor Deposition (MOCVD) process was employed. The effect of H₂O vapor on the grain size, deposition rate, and resistivity was examined. Electrical resistivities of 2.4 cm for copper films deposited on Si(100) and 3.44 cm for copper films deposited on glass at substrate temperatures of 265° C and a [Cu(acac)₂] source temperature of 147° C with the use of H₂O vapor were measured. When [Cu(HFA)₂] was used, the substrate temperature was 385° C and the source temperature was 85° C. An activation energy for the copper film deposition process was calculated to be 22.2 kJ/mol in the case of the [Cu(acac)₂] source. A deposition rate of 11 nm/min was obtained with Cu(acac)₂ as the source and the rate was 44.4 nm/min with the Cu(HFA)₂ source; both were obtained with the use of H₂O vapor. No selectivity was observed with either source for either substrate. The deposited films were fully characterized using XRD, LVSEM, SAXPS, and RBS.     

Intrinsic theory of projective changes in Finsler geometry

The aim of the present paper is to provide an intrinsic investigation of projective changes in Finsler geometry, following the pullback formalism. Various known local results are generalized and other new intrinsic results are obtained. Nontrivial characterizations of projective changes are given. The fundamental projectively invariant tensors, namely, the projective deviation tensor, the Weyl torsion tensor, the Weyl curvature tensor and the Douglas tensor are investigated. The properties of these tensors and their interrelationships are obtained. Projective connections and projectively flat manifolds are characterized. The present work is entirely intrinsic (free from local coordinates) (arXiv:?0904.?1602 [math.DG]).     

A semi-coherent interface with nanoledges intersecting the free surface of an elastic half-space

Abstract

The elastic field generated by a semi-coherent interface formed by a succession of parallel terraces and nanoledges is investigated when the interface intersects the free surface of an isotropic half-space medium. The method uses the combination of semi-infinite Somigliana dislocations placed on each terrace and semi-infinite translation (or Volterra) dislocations placed at one or two corners of the nanoledges. Numerical examples depict the deformation fields nearby emerging regions of two semi-coherent interfaces; one is flat, while the other includes nanoledges.     

Molecular modeling simulation and experimental measurements to characterize chitosan and poly(vinyl pyrrolidone) blend interactions

Blends of chitosan and poly(vinyl pyrrolidone) (PVP) have a high potential for use in various biomedical applications and in advanced drug‐delivery systems. Recently, the physical and chemical properties of these blends have been extensively characterized. However, the molecular interaction between these two polymers is not fully understood. In this study, the intermolecular interaction between chitosan and PVP was experimentally investigated using ¹³C cross‐polarization magic angle‐spinning nuclear magnetic resonance (¹³C CP/MAS NMR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). According to these experimental results, the interaction between the polymers takes place through the carbonyl group of PVP and either the OH? C₆, OH? C₃, or NH? C₂ of chitosan. In an attempt to identify the interacting groups of these polymers, molecular modeling simulation was performed. Molecular simulation was able to clarify that the hydrogen atom of OH? C₆ of chitosan was the most favorable site to form hydrogen bonding with the oxygen atom of C?O of PVP, followed by that of OH? C₃, whereas that of NH? C₂ was the weakest proton donor group. The nitrogen atom of PVP was not involved in the intermolecular interaction between these polymers. Furthermore, the interactions between these polymers are higher when PVP concentrations are lower, and interactions decrease with increasing amounts of PVP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1258–1264, 2008