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71.
Barbara Le?niewska Monika Kosi��ska Beata Godlewska-?y?kiewicz El?bieta Zambrzycka Agnieszka Z. Wilczewska 《Mikrochimica acta》2011,175(3-4):273-282
An ion-imprinted polymer (IIP) was obtained by copolymerization of methacrylic acid (as a functional monomer) and ethylene glycol dimethacrylate (as a crosslinking agent) in the presence of various chelators for Pt(II) ion and using 2,2??-azo-bis-isobutyronitrile as the initiator. Specifically, acetaldehyde thiosemicarbazone (AcTSn) and benzaldehyde thiosemicarbazone (BnTSn) were used as chelators. The IIPs were applied as sorbents for solid-phase extraction of Pt(II) and Pt(IV) ions from aqueous solutions. The effects of acidity and flow rate of the sample, of elution conditions and of potentially interfering ions were investigated. The imprinting effect of analyte is clearly demonstrated by the fact that only the IIP is capable of quantitative retention of Pt(II) and Pt(IV) ions. The method works best in the pH range from 0.5 to 1 and from 3.5 to 9.5. The ions can be recovered with an acidic solution of thiourea. The Pt-AcTSn polymer displays better sorption properties for the separation of analytes. The selectivity coefficients of the Pt-AcTSn and control polymers for Pt(IV) in the presence Pd(II), Rh(III), Ru(III), Al(III) and Cu(II) were calculated, and the sorbent capacity for Pt(IV) was found to be 4.56???g?g?-1. The method was successfully applied to the determination of Pt(IV) by electrothermal atomic absorption spectrometry in tap water, tunnel dust and anode slime samples. Figure
The new ion imprinted polymers based on Pt(II)-thiosemicarbazone derivative chelates were prepared and used as solid phase extraction sorbent for selective separation of platinum. The method was successfully applied to the determination of analyte in environmental samples by electrothermal atomic absorption spectrometry 相似文献
72.
Wozniak B Zuchowska IM Zmudzki J Jedziniak P Korycinska B Sielska K Witek S Klopot A 《Analytica chimica acta》2011,700(1-2):155-166
Liquid chromatography tandem mass spectrometry methods were developed and validated to screen for and confirm residues of the thyreostatic drugs: tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil in bovine and porcine urine and muscle tissues using dimethylthiouracil as internal standard. Thyreostats were extracted from urine samples with diethyl ether after derivatisation with 3-iodobenzylbromide in basic medium (pH 8.0) and analyzed by gradient elution on a Nucleosil C18 column with ion trap mass spectrometry detection using an electrospray source and triple quadrupole MS detection with turbo spray source. Thyreostats were extracted from muscle tissue with methanol, the denaturation of matrix protein was performed and then the same steps as for the urine samples were carried out. The methods were validated in accordance with the Commission Decision 2002/657/EC. Good thyreostats recoveries were obtained (from 82% to 117%) as well as acceptable within-lab reproducibility. The values of the decision limit CCα and the detection capability CCβ of five thyreostatic drugs are found to be below the recommended concentration set at 10 μg L(-1) (kg(-1)). The results of the validation demonstrate that liquid chromatography mass spectrometry with ion trap detection does not meet the criteria for confirmation for some thyreostats and therefore was applied for screening purpose only. 相似文献
73.
Heger D Nachtigallová D Surman F Krausko J Magyarová B Brumovský M Rubeš M Gladich I Klán P 《The journal of physical chemistry. A》2011,115(41):11412-11422
A combined experimental-computational approach was used to study the self-organization and microenvironment of 1-methylnaphthalene (1MN) deposited on the surface of artificial snow grains from vapors at 238 K. The specific surface area of this snow (1.1 × 10(4) cm(2) g(-1)), produced by spraying very fine droplets of pure water from a nebulizer into liquid nitrogen, was determined using valerophenone photochemistry to estimate the surface coverage by 1MN. Fluorescence spectroscopy at 77 K, in combination with molecular dynamics simulations, and density functional theory (DFT) and second-order coupled cluster (CC2) calculations, provided evidence for the occurrence of ground- and excited-state complexes (excimers) and other associates of 1MN on the snow grains' surface. Only weak excimer fluorescence was observed for a loading of 5 × 10(-6) mol kg(-1), which is ~2-3 orders of magnitude below monolayer coverage. However, the results indicate that the formation of excimers is favored at higher surface loadings (>5 × 10(-5) mol kg(-1)), albeit still being below monolayer coverage. The calculations of excited states of monomer and associated moieties suggested that a parallel-displaced arrangement is responsible for the excimer emission observed experimentally, although some other associations, such as T-shape dimer structures, which do not provide excimer emission, can still be relatively abundant at this surface concentration. The hydrophobic 1MN molecules, deposited on the ice surface, which is covered by a relatively flexible quasi-liquid layer at 238 K, are then assumed to be capable of dynamic motion resulting in the formation of energetically preferred associations to some extent. The environmental implications of organic compounds' deposition on snow grains and ice are discussed. 相似文献
74.
Nowicka B Bałanda M Gaweł B Ćwiak G Budziak A Łasocha W Sieklucka B 《Dalton transactions (Cambridge, England : 2003)》2011,40(12):3067-3073
Methanol adsorption into the porous 2D bimetallic coordination network {[Ni(cyclam)](3)[W(CN)(8)](2)}(n) (cyclam = 1,4,8,11-tetraazacyclotetradecane) causes significant modification of its structure and magnetic properties. Fully reversible transformations between the three states of the network: anhydrous, hydrated and methanol-modified are observed with the transition to the magnetic ordered state at T(c) equal to 4.9 K, 8.3 K and 11.4 K respectively. All three phases have a metamagnetic character but the methanol-modified one most easily turns to ferromagnetic and shows a hysteresis loop with coercivity field of 250 Oe. The differences in magnetic behaviour of the anhydrous and guest-induced forms of the compound are discussed in terms of changes in the structure: CN-bridge geometry and distance between the layers. 相似文献
75.
Piotr Kowalski Jolanta Jaśkowska Andrzej J. Bojarski Beata Duszyńska Adam Bucki Marcin Kołaczkowski 《Journal of heterocyclic chemistry》2011,48(1):192-198
The synthesis and evaluation as 5‐HT1A and 5‐HT7 serotonin receptor ligands of the two sets of O‐substituted hydroxybenzamides, structurally related to 2‐{3‐[4‐(2‐methoxyphenyl)piperazin‐1‐yl]propoxy}benzamide ( 1 ), (Ki 5‐HT1A = 21 nM, 5‐HT7 = 234 nM) are reported. To affect the affinity for 5‐HT1A and 5‐HT7 receptors, an amide moiety ( 2 , 3 , 4 , 5 , 6 ) and a hydrocarbon chain length ( 7 , 8 , 9 , 10 ) were modified. The serotonergic activity of compounds 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 was generally higher in the case of 5‐HT1A receptors compared with 5‐HT7 ones; the most active 5‐HT1A ligands being meta‐isomer 2 (Ki = 7 nM) and both analogs of 1 with the longest spacer, i.e., penta‐ and hexa‐methylene derivatives 9 and 10 (Ki = 4 and 3 nM, respectively). The observed biological properties of compounds 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 were elucidated using molecular modeling procedures. J. Heterocyclic Chem., (2010). 相似文献
76.
Beata Podkościelna 《Journal of Thermal Analysis and Calorimetry》2011,104(2):725-730
The thermal stability of the ionic liquids (ILs) 1-n-butyl-3-methylimidazolium bromide, [BMIM]Br, and 1-n-octyl-3-methylimidazolium bromide, [OMIM]Br, was evaluated through thermogravimetry (TG). Long-term isothermal TG studies
revealed that both of these ILs exhibit appreciable decomposition even at temperatures significantly lower than the onset
decomposition temperature, previously determined from fast scan TG experiments. The long-term TG studies of both the ILs showed
linear mass loss as a function of time at each temperature of 10 °C interval in the range 533–573 K over a period of 10 h.
The kinetics of isothermal decomposition of ILs was analyzed using pseudo-zero-order rate expression. The activation energies
for the isothermal decomposition of [BMIM]Br and [OMIM]Br under nitrogen atmosphere are 219.86 and 212.50 kJ mol−1, respectively. The moisture absorption kinetics of these ILs at 25 °C and 30% relative humidity (RH) and at 85 °C and 85%
RH were also studied. Water uptake of ILs exposed at 25 °C/30%RH follows a simple saturation behavior in agreement with Weibull
model while that at 85 °C/85%RH fortuitously fit into the Henderson–Pabis model. 相似文献
77.
Simeonika Rangełowa‐Jankowska Dawid Jankowski Dr. Beata Grobelna Prof. Ignacy Gryczyński Prof. Zygmunt Gryczyński Dr. Robert Bogdanowicz Prof. Piotr Bojarski 《Chemphyschem》2011,12(13):2449-2452
The first observation of strong directional surface‐plasmon‐coupled emission (SPCE) of Rhodamine 110 in silica nanofilms deposited on silver nanolayers is reported. The preparation of the material is described in detail. The intensity of SPCE exceeds 10 times that of free space fluorescence and total linear light polarization in the SPCE ring is observed. A new experimental setup and an original data collection method is presented. Our material completely preserves its fluorescence properties for at least eight months. 相似文献
78.
Wileńska B Danikiewicz W Bugaj M Kamieńska-Trela K Krówczyńsk A 《European journal of mass spectrometry (Chichester, England)》2011,17(3):237-243
Electron ionization (EI) and positive electrospray ionization (ESI) mass spectra of selected diaryl enaminoketones and enaminothiones have been studied. In the EI mass spectra of both classes of compound, molecular ion peaks are accompanied by the peaks corresponding to the [M-H](+) ions. The formation of these ions can be rationalized by a cyclization reaction resulting in the formation of the respective isoxazolium and isothiazolium cations. Under positive ESI conditions, in the spectra recorded for the enaminoketones peaks corresponding to the [M+H](+), [M+Na](+) and [2M+Na](+) ions appeared, while in the spectra recorded for the enaminothiones, peaks corresponding to the [M-H](+) ions were dominant. These ions are most likely formed by oxidation of the neutral enaminothione molecules on the surface of the positively charged stainless steel capillary in the ESI ion source (anodic oxidation). 相似文献
79.
The oxidation process of 1-methoxy-4-(1-methylethyl)benzene catalysed by N-hydroxyphthalimide (NHPI) or NHPI in combination
with Cu(II), Co(II), Mn(II) and Fe(II) salts was studied. The effects of the amount of catalyst and the temperature were determined.
1-Methyl-1-(4-methoxyphenyl)ethyl hydroperoxide was obtained in a yield of 73 mol% when 1-methoxy-4-(1-methylethyl)benzene
was oxidised for 3 h at 60°C in acetonitrile as a solvent in the presence of NHPI. 1-(4-Methoxyphenyl)ethanone with high selectivity
up to 68–75 mol%, but low yield amounting to 11 mol% was obtained when 1-methoxy-4-(1-methylethyl)benzene was oxidised in
the presence of the NHPI/Cu(II) system at 120°C.
相似文献
80.
Aequationes mathematicae - For a family $$(\mathscr {A}_x)_{x \in (0,1)}$$ of integral quasi-arithmetic means satisfying certain measurability-type assumptions we search for an integral mean K such... 相似文献