Multi-residue analytical method for human pharmaceuticals and synthetic hormones in river water and sewage effluents by solid-phase extraction and liquid chromatography–tandem mass spectrometry

Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm³, 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC–ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.     

Coordination of carbonyl oxygen in the complexes of polymeric <Emphasis Type="Italic">N</Emphasis>-crotonyl-2-hydroxyphenylazomethine

The Schiff base N-crotonyl-2-hydroxyphenylazomethine HL, derived from the reaction of acrylamide and salicylaldehyde, was synthesised. Polymeric complexes were obtained from the reaction of polymeric HL with divalent metals. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods and compared with that previously reported for the analogous monomeric ligand. These studies revealed tetrahedral geometries around the metal centres for Mn(II), Co(II), Zn(II), Cd(II) and Hg(II) complexes of general formula [M(L)Cl], octahedral for Ni(II) and Cu(II) complexes of general formula [M′(L)Cl(H₂O)₂], and square planar for Pd(II) complex of general formula [Pd(L)Cl].     

Theoretical Studies on Novel Gridspiroarenes: Structures,Noncovalent Interactions and Reorganization Energies

Organic semiconductor materials with low reorganization energy have various applications such as in organic light‐emitting diodes (OLEDs), organic field‐effect transistor (OFETs) and organic solar cells (OSCs). In this work, we have designed a new class of gridspiroarenes (GS‐SFX and GS‐SITF) with #‐shaped structures, which have novel crisscross geometrical structures compared to widely used spirocyclic arenes—SFX and SITF. The structure electronic properties, adiabatic ionization potentials (IP_a), adiabatic electron affinities (EA_a) and reorganization energies (λ) of GS‐SFX and GS‐SITF have been calculated using density functional theory (DFT) method. The calculated HOMO and LUMO spatial distributions suggest that GS‐SFX and GS‐SITF have better transport properties. The noncovalent interaction analysis shows the weak intramolecular interactions between their arms. The results indicate that the reorganization energies of GS‐SFX and GS‐SITF are significantly reduced compared to the dimer structures—DSFX and DSITF. Furthermore, the GS‐SITF1 which is one of the isomers of GS‐SITF exhibits the lowest values for λ(h) (0.067 eV) and λ(e) (0.153 eV). Therefore, we believe the predicted structure, electronic property, and reorganization energy are good indicator for transport materials. This work has systematically studied the effect of gridization, which provides insights to design organic semiconductor materials with excellent charge transport properties.     

配合物(BenzMeIm)2[PtCl4]的合成与表征

通过离子液体氯化1-苄基-3-甲基咪唑（BenzMeIm-Cl）与PtCl₂的反应,合成了配合物（BenzMeIm）₂[PtCl₄],并用元素分析、红外光谱、紫外-可见光谱、¹H NMR、¹³C NMR和单晶X射线衍射对其进行了表征。单晶X射线分析表明,配合物结构属于P2₁/c空间群,晶胞参数和结构解析参数为：a=0.981 80（5）nm,b=0.861 47（3）nm,c=0.144 332（7）nm,β=92.480（2）°,V=121.96（1）nm³,R₁=0.014 4,wR₂=0.038 8。     

Application of nickel phosphate nanoparticles and VSB-5 in the modification of carbon paste electrode for electrocatalytic oxidation of methanol

Carbon paste electrodes were modified by nickel phosphate nanoparticles and nickel phosphate Versailles Santa Barbara-5 molecular sieves. Then, transition metal ions of Ni(II) were incorporated to the nickel phosphate by immersion of the modified electrode in a 0.1-M nickel chloride solution. The electrochemical behaviors of the modified electrodes were studied using cyclic voltammetry. These modified electrodes were used as anode for the electrocatalytic oxidation of methanol in alkaline medium. The influence of some parameters such as different molecular sieves, scan rate of potential, and methanol concentration was investigated on the anodic peak height of the methanol oxidation. The best result was obtained by nickel phosphate nanoparticles.     

An innovative electrochemical approach for voltammetric determination of levodopa using gold nanoparticles doped on titanium dioxide nanotubes

Catalytic nanotubes made from titanium dioxide (TiO₂-NTs) and covered with gold nanoparticles (Au-NPs) were prepared via galvanic deposition of the Au-NPs on the TiO₂-NTs. The morphology and surface characteristics of the resulting electrodes were investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results indicated that the Au-NPs were homogeneously deposited on the surface of TiO₂-NTs which consist of individual tubes of about 40?C80?nm in diameter. The AuNPs with a size of 80?C100?nm are well-dispersed on the surface of the TiO₂-NTs. The electro-catalytic activity of the electrodes towards the electro-oxidation of levodopa was studied by cyclic voltammetry, differential puls voltammetry. The results showed that the electrodes exhibit a considerably higher activity toward the oxidation of levodopa. The oxidation peak current linearly depends on the concentration of levodopa in the 10 to 70???M concentration range. Levodopa was determined by the method in pharmaceutical preparations, and results were found to be satisfactory.

CdSe sensitized thin aqueous films: probing the potential distribution inside multilayer assemblies

Ultrathin polypeptide multilayer films are assembled by the sequential electrostatic adsorption of monolayers of poly-l-lysine and poly-l-glutamic acid onto carboxylic acid terminated alkanethiol-modified gold surfaces. The polypeptide multilayer films are hydrophilic, can incorporate electroactive species such as ferri/ferrocyanide, and are stable when immersed in organic solvents such as 1,2-dichloroethane. Cadmium selenide quantum dots stabilized by negatively charged citrate groups are electrostatically attached to the multilayer film assembly in order to act as photoactive species. Photocurrent responses originating from the CdSe sensitized ultrathin multilayer film are investigated as functions of the applied potential, the thickness of the film and the presence of quenchers in the organic phase. A theoretical model is proposed in order to analyze the kinetics of the photoinduced electron-transfer reactions and to probe the potential distribution within the film.     

Preparation and characterization of new sol–gel titanium(IV) butoxide–cyanopropyltriethoxysilane hybrid sorbent for extraction of polar aromatic amines

A new titanium(IV) butoxide-cyanopropyltriethoxysilane (Ti-CNPrTEOS) hybrid material was successfully synthesized for the use as sorbent for the extraction of polar aromatic amines. The sorbent was synthesized by hydrolysis and condensation of titanium(IV) butoxide and cyanopropyltriethoxysilane with the presence of hydrochloric acid as catalyst via sol–gel method. Several factors influencing the synthesized sorbent such as solvent selection, mol of water content, ratio of titanium(IV) butoxide and cyanopropyltriethoxysilane and aging temperature were investigated and optimized. The sorbents were characterized by fourier transform-infrared, field-emission scanning electron microscopy-energy, CHN elemental analysis and thermogravimetric analysis. The applicability of the sorbents for the extraction of polar aromatic amines by the batch sorption method was extensively studied and evaluated. Under the optimum synthesis conditions (tetrahydrofuran as solvent, 1.2 M of hydrochloric acid catalyst, 4 mol of water content with ratio of titanium(IV) butoxide and cyanopropylteriethoxysilane of 1:1 and aging temperature of 60 °C), the extraction showed high recovery towards the extraction of polar aromatic amines. The synthesized sorbent was successfully applied for the extraction of selected aromatic amines via batch sorption method in waste water samples prior to the gas chromatography-flame ionization detector separation. The synthesized sol–gel Ti-CNPrTEOS sorbent demonstrated the potential as an alternative extraction sorbent with higher selectivity towards polar aromatic amines.