bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological and integrated chemical–biological treatment of PCB congeners in soil/sediment‐containing systems
Authors: Aronstein Boris N. , Rice Laura E. 
Published: May 2005

AbstractA series of experiments was conducted on the integrated chemical–biological treatment of 14C‐labelled polychlorinated biphenyl congeners in soil/sediment‐containing systems. The hydroxyl radicals, generated by Fenton's reagent (1% (v/v) H2O2, 1 mmol dm−3 FeSO4), followed by inoculation with Pseudomonas sp., strain LB400, and Alcaligenes eutrophus, strain H850, increased the overall extent of 2‐chlorobiphenyl mineralisation in slurries of contaminated manufactured gas plant soil and sediment by 2·9 and 7·4 times, respectively, compared with biodegradation alone. In uncontaminated topsoil slurries the effect of chemical pretreatment was not observed. In the systems amended with 2,2′,4,4′‐tetrachlorobiophenyl, the application of Fenton's reagent increased the overall extent of mineralisation by 2·4 times, compared with the biological treatment alone, but had no effect in the slurries of contaminated soil and sediment. The increased level of radioactivity in the liquid phase of experimental systems suggests that intermediates produced in the process of chemical oxidation are less hydrophobic than parent polychlorinated biphenyls and therefore more available for further biodegradation.
A novel multienzyme electrode for the determination of citrate
Authors: Gajovic Nenad , Warsinke Axel , Scheller Frieder W. 
Published: May 2005

AbstractA novel amperometric biosensor for the determination of citric acid in food samples and fermentation broths has been developed. The sensor is composed of citrate lyase (CL, EC 4.1.3.6), oxaloacetate decarboxylase (OAC, EC 4.1.1.3) and pyruvate oxidase (POP, EC 1.2.3.3), co‐immobilized in gelatin, and an amperometric transducer. A Clark‐type O2‐electrode and a modified Clark‐type H2O2‐electrode were alternatively used as a transducer. The biosensor covers a linear detection range from 1 μmol dm−3 to 1 mmol dm−3 citrate, with a response time of 2·5 min for the steady state response. The lower detection limit for citrate is 0·5 μmol dm−3. The response of the sensor remained constant for 8 days and decreased to 25% after 18 days at 20–23°C. The results obtained from citrate determinations in food samples and fermentation broths agree well with those determined by enzymatic sample anlaysis. The relative standard deviation for citrate determinations with the new biosensor was 2·2% (n = 7).
Performance enhancement with tapered anaerobic fluidized‐bed bioreactors
Authors: Wu Chun‐Sheng , Huang Ju‐Sheng 
Published: May 2005

AbstractThe substrate removal efficiencies of the conventional (taper angle of 0°) and three tapered anaerobic fluidized‐bed bioreactors (tape angles of 2·5°, 5° and 10°) predicted from a kinetic model correlated with the average biofilm thickness measured. The predicted substrate removal efficiencies of the three tapered bioreactors were higher than that of the conventional bioreactor. This result was also confirmed by the experimental study, implying the performance of the conventional bioreactor can be significantly enhanced by changing the geometrical configuration to a tapered form. Moreover, the rate‐limiting step of acetate methanogenesis in the bioreactors was reaction‐controlled and the biofilm was fully‐penetrated.
Activated sludge treatment of wash waters derived from the purification of virgin olive oil in a new manufacturing process
Authors: Borja Rafel , Alba José , Banks Charles J. 
Published: May 2005

AbstractEffluent derived from the washing of virgin olive oil in a new manufacturing process was found to be readily treated using a completely mixed activated sludge process. The biokinetic coefficients for the process were derived by operating laboratory‐scale plant at four different input chemical oxygen demand (COD) concentrations and four differing solids retention times. Results showed effluent COD to be correlated with input feed growth and proportional to the product of feed strength and specific growth rate. The proportional to the product of feed strength and specific grown rate. The multiple‐substrate model of Admas et al. fitted the data well and could be used productively to determine effluent COD from a wide range of input substrate concentrations.
Removal of the tetravalent actinide thorium from solution by a biocatalytic system
Authors: Young Ping , Macaskie Lynne E. 
Published: May 2005

AbstractThe aim of this work was to study the effects of pH, a metal complexing reagent (citrate) and the concentration of substrate on the bioaccumulation of tetravalent actinides, using Th4+ as a model, by a phosphates‐catalysed reaction. This yields HPO which precipitates with heavy metals as cell‐bound metal phosphate. Poor removal of The from solution was observed, which is in accordance with the solution chemistry of the metal. A considerable improvement in the efficiency of thorium removal was obtained by incorporating ammonium acetate (NH4Ac) into the solution. Although extensive deposition of polycrustaling NH4UO2PO4 was observed previously by cells that had accumulated UO, no evidence for deposition of cstalline thorium phosphate was obtained by X‐ray diffraction analysis. Examination by proton induced X‐ray emission (PIXE) analysis. Examination by proton induced X‐ray emission (PIXE) analysis showed a non‐homogenous thorium deposit of variable phosphorous content.
The swelling of a low‐rank coal in benzene–pyridine and toluene–pyridine mixtures
Authors: Jones J. Clifford , Prawistasari Bayu 
Published: May 2005

AbstractA low‐rank coal is examined for swelling in benzene–pyridine and toluene–pyridine mixtures. In each case, swelling is shown to mainly due to the pyridine, the action of which is specific and not amenable to interpretation by the solubility parameter approach to understanding coal swelling.
Contrasting adsorption exhibited by lignite‐based activated carbons
Authors: Allen Stephen J. , Balasundaram Vikram , Armenante Piero M. , Thom Linda , Kafkewitz David 
Published: May 2005

AbstractThe adsorption of sodium benzoate, 2,4‐dichlorophenol and 2,4,6‐trichlorophenol onto five activated carbons made from Northern Ireland lignite is reported. A Two‐stage process consisting of chemical activation during the charring of the lignite, followed by steam activation was used to produce the activated carbons. The adsorption equilibrium isotherms obtained for the carbons have been plotted to obtain the Freundlich, Langmuir and Redlich Peterson constants. Chemical and steam activation methods both produced improvements to the carbon performance on their own, with the combination of the two treatments providing the best results. In the main the chemical treatment providing the best improvement on its own also gave the biggest improvement when combined with steam treatment. BET surface area measurements made using nitrogen adsorption correlate strongly with the capacity for benzoate adsorption.
Additives from aromatic extracts
Authors: Mohamed Mohamed M. , El Naga Hamdi H. Abou , El Meneir Mohamed F. 
Published: May 2005

AbstractAromatic extract residues, as by‐products, are accumulated in local refineries through the refining of lubricating oils. These residues are dealt with as low economic value products, even their disposal imposes serious problems to the refineries. Therefore, the present work is aimed at upgrading these residues by using them to synthesis some different petroleum additives, e. g. antioxidants, ashless dispersant additives, pour point depressants and flow improvers for crankcase lubricating oils and fuels. Antioxidants are synthesised by reacting mono‐aromatics with phosphorus pentasulphide (P2S5) in the presence of zince oxide (ZnO). Ashless dispersant additives are synthesised by reacting alkylated mono‐aromatics (using chlorinated paraffin wax as alkylating agent) with formaldehyde solution (37%) in the presence of polyisobutylene succinimide. Pour point depressants and flow improvers are synthesised by acylating di‐aromatics via a Friedel‐Crafts' reaction. Comparative evaluation of the performance of the synthesised products with commercial additives showed their good efficiency.
Separation of phenylacetic acid, 6‐aminopenicillanic acid and penicillin G with electrodialysis under constant current
Authors: Chen Dong‐Hwang , Wang Sung‐Shyong , Huang Ting‐Chia 
Published: May 2005

AbstractThe separation behavior of phenylacetic acid (PAA), 6‐aminopenicillanic acid (6‐APA) and penicillin‐G (Pen‐G) with electrodialysis under constant current was studied. The effects of ionic concentrations and current density on their separation behavior were investigated. The sorption of PAA, 6‐APA and Pen‐G and in the anion exchange membrane, and the variations of the applied voltage and current efficiencies with time during electrodialysis were also examined. It was found that the molecular size and the affinity toward the anion exchange membrane played a key role for the electrodialysis of PAA, 6‐APA and Pen‐G. Phenylacetic acid had the lowest affinity toward the membrane but the fastest transport rate. Penicillin‐G had the highest affinity toward the membrane but the slowest transport rate. With the increase of Pen‐G concentration, the concentration polarization of Pen‐G in the vicinity of anion exchange membrane became very serious, which severely retarded the transport of PAA and 6‐APA. Although the increase of current density accelerated the transport of PAA, 6‐APA and Pen‐G, more serious concentration polarization of Pen‐G occurred and the separation ratio of PAA to 6‐APA decreased.
Transport and separation of cobalt, nickel and copper ions with alamine liquid membranes
Authors: Marchese José , Campderrós Mercedes , Acosta Adolfo 
Published: May 2005

AbstractThe transfer and separation of Co(II), Ni(II) and Cu(II) ions across a flat‐sheet supported liquid membrane containing Alamine 336 as the mobile carrier dissolved in kerosene solvent has been investigated. Both the Alamine composition in the organic solution and the hydrochloric acid concentration in the feed solution have a marked effect on Co(II) and Cu(II) transport. A maximum flow of these ions at 50% of Alamine in the diluent was obtained. Ni(II) ion was not transported in the whole range of experimental conditions studied and good separation from Co(II) and Cu(II) could thus be performed. With decreasing hydrochloric acid concentration in the feed solution the separation factor of Cu(II) from Co(II) increases thus decreasing the Cu(II) recuperation factor.
The effect of cobalt on the activation of fused iron catalyst for ammonia synthesis
Authors: Kaleńczuk Ryszard J. 
Published: May 2005

AbstractBET, scanning electron microscopy, X‐ray diffraction, Mössbauer spectroscopy, X‐ray fluorescence spectroscopy and McBain thermobalance were used to investigate the effect of cobalt on the reduction behavior and activity of used iron catalyst for ammonia synthesis. Activity tests were carried out under 10 MPa in the 350–450°C temperature rang. Studies were performed on the traditional multipromoted iron catalyst and on the series of catalysts prepared with addition of cobalt. Addition of cobalt promoted the iron catalyst for ammonia synthesis. The most active sample was that containing approx. 5.5% wt Co. Cobalt changed the reduction behavior of the catalyst. The rate of the surface change during reduction was higher for the case of the ‘cobalt catalyst’; however the rate of mass change was higher for a typical iron catalyst. The process of reduction was probably followed by the formation of an Fe3Co compound and by the surface faceting, with the exposure of an Fe(111) plane.
Gradient elution under hydrostatic equilibrium in liquid chromatography. Part 1
Authors: Said A. S. 
Published: May 2005

AbstractThe theory of gradient elution under hydrostatic equilibrium is developed for the case where only one reservoir and one mixing chamber are used and where both solvents have equal densities. Given the shapes of the two vessels, effluent concentration curve equations are deduced for different mixing chamber‐reservoir combinations. On the other hand, given the equation for the effluent concentration curve, the reservoir cross‐sectional area, as a function of height, can be deduced when the mixing chamber has a constant cross‐section. The varying cross‐section of the reservoir is accomplished by inserting thin discs of different areas on top of one another inside a regular vessel of constant cross‐section.Except for complicated gradients, a given gradient can be accomplished using a reservoir with a cross‐sectional area which varies linearly with height. In the case of complex gradients, a reservoir having two or more linear segments becomes necessary. A numerical method is given for the calculation of the continuously varying reservoir cross‐section for the exact duplication of a given gradient.
Determination of triphenyltin hydroxide derivatives by capillary GC and tin‐selective FPD
Authors: Wright B. W. , Lee M. L. , Booth G. M. 
Published: May 2005

AbstractA new method for the determination of triphenyltin hydroxide using capillary column gas chromatography with a tin‐selective flame photometric detector has been developed. Triphenyltin hydroxide and its potential metabolites are converted to methyl derivatives and separated on glass capillary columns coated with OV‐101. Derivatization of triphenyltin hydroxide, triphenyltin chloride, diphenyltin dichloride, phenyltin trichloride, and bis‐triphenyltin oxide is nearly quantitative with a minimum of redistribution products. The selectivity of the flame photometric detector is cearly demonstrated by the comparison of chromatographic profiles obtained from using both the flame photometric and flame ionization detectors.The use of this chromatographic system in the analysis of triphenyltin hydroxide in a fortified water sample demonstrates the potential use of this system in organotin residue chemistry.
Effects of trapping temperature and film thickness in purge and trap with whole column cryotrapping on fused silica columns
Authors: Pankow J. F. 
Published: May 2005

AbstractThe effects of trapping temperature and column film thickness were investigated with respect to their ability to promote effective cryofocusing on fused silica capillary columns. The study was a further development of the purge and trap with whole column cryotrapping (P&T/WCC) method. The rates at which compounds could be thermally desorbed from a P&T unit and transferred to a column (with zero split) were first examined. A near quantitative transfer of the desorbable analytes was obtained with a 4 min, 180°C, 20 mL/min desorption. The compounds tested included naphthalene. Columns with film thicknesses from 0.12 to 3.0 μm were then investigated in P&T/WCC analyses with WCC temperatures ranging from −80 to 0°C. The trapping took place from a transfer line gas stream initially at 175°C. The volatilities of the compounds examined varied from that of 1,1‐dichloroethene to 1,1,2,2‐tetrachloroethane. A higher film thickness was found to ease the WCC temperature requirements. Within each column type, the warmest WCC temperatures which allowed good cryotrapping with no significant increases in peak width were: 0.25 μm, −70°C; 1.0 μm, −50°C; 3.0 μm, −20°C. In addition to being quantitative, the trapping provided good chromatography.
Capillary GC analysis of diesel fuels using simultaneous parallel triple detection
Authors: Williams P. T. , Bartle K. D. , Mills D. G. , Andrews G. E. 
Published: May 2005

AbstractDiesel fuels from different parts of the UK have been analyzed for polycyclic aromatic hydrocarbons (PAH), nitrogen‐containing PAH, and sulfur‐containing PAH using capillary column GC with simultaneous parallel triple detection. The concentrations of polyaromatic compounds (PAC) were high and showed considerable variability amongst the fuels. The PAH are mainly naphthalene, fluorene, and phenanthrene and their alkylated homologs; the PANH are mainly carbazole and its methyl derivatives; the PASH are mainly dibenzothiophene and its methyl derivatives.
Preparation, evaluation, and comparison of wide bore (320 μm) and narrow bore (50 μm) cyanosilicone‐coated capillary columns for gas chromatography
Authors: Aerts A. , Rijks J. , Bemgard A. , Blomberg L. 
Published: May 2005

AbstractThe preparation of wide bore (320 μm) and narrow bore (50 μm) fused silica capillary columns is described for immobilized cyanopropyl substituted silicones containing 60 and 88% substitution. The effect of high temperature deactivation with cyanopropylcyclosiloxanes was studied with a special test mixture. Curing was achieved with dicumyl peroxide or azo‐tert‐butane.The columns were evaluated and compared in terms of efficiency, activity, polarity, and temperature stability. Different coating methods were compared for the narrow bore columns. The activity of the 60% cyanopropyl columns that had been immobilized with dicumyl peroxide was significantly larger than for azo‐tert‐butane immobilized columns. The polarity of polar columns appeared to depend greatly on column temperature and is completely different for wide and narrow bore columns.
Further applications for capillary gas chromatography in routine quantitative toxicological analyses
Authors: Phillips A. Maury , Logan Barry K. , Stafford David T. 
Published: May 2005

AbstractThe use of capillary column gas chromatography for drug screening in forensic toxicology has become increasingly widespread. Screening procedures however are often lengthy and unsuitable for rapid confirmatory or quantitative applications. In order to develop a practical scheme for confirmatory/quantitative analysis, we have optimized a series of temperature profiles to allow the rapid quantitative determination of a wide range of acid/neutral and basic drugs in extracts from post mortem fluids and tissue. The appropriate profile is selected based on the retention index on a standard crosslinked methyl silicone column used to screen extracts. The use of a 5% phenyl methyl silicone phase allows complementary identification, and allows the separation of some pairs of compounds with identical retention indices in the screning procedure.
Optimization and application of the large volume on‐column introduction (LOCI) technique for capillary GC with preliminary on‐line capillary solvent distillation/concentration
Authors: Hiller Joseph F. , McCabe Terry , Morabito Paul L. 
Published: May 2005

AbstractThis report describes an on‐line capillary GC injection system which enables on‐column injection of a hundred or more microliters, and yields separations comparable with those obtained from on‐column injection of 1–2 microliters of solutions a hundred times more concentrated. Precision, carry‐over, linearity, and discrimination are comparable with those of classical sample‐introduction techniques. A selection of polar and high boiling compounds has been examined, and excellent peak shapes obtained for hundreds of injections. Initial results indicate that maintenance and long‐term reproducibility will also be comparable with those of classical techniques.The instrument utilizes a version of the large volume on‐column injector with solvent diversion described in an earlier communication, with the addition of a method for independent heating of the retention gap. This modification reduces the effects of activity in the retention gap and improves the capability of the technology to handle complex mixtures. It also increases reliability and system lifetime, fits readily into most GC ovens, is easily automated, and should be compatible with all capillary GC detectors.
Confirmation of anabolic hormone residues in bovine blood by micro‐HPLC–ion spray–tandem mass spectrometry
Authors: Draisci Rosa , Giannetti Luigi , Lucentini Luca , Palleschi Luca , Purifacto Ivana , Moretti Gabriella 
Published: May 2005

AbstractSensitive, specific analytical methods for the determination of an‐abolics in biological matrices are essential to control the illegal use of these substances in food‐producing animals. Programs of residue control are performed annually in Italy for the determination of endogenous sex hormones (17β‐estradiol, progesterone, testoster‐one) for which maximum physiological levels have been established. At present the methods used in the Italian programs to determine natural hormones in bovine blood are based on the sensitive radio‐immunoassay (RIA), due to relatively low levels of these substances in plasma/serum. In this study, we report a new method based on tandem mass spectrometry with on‐line micro‐high performance liquid chromatography (micro‐HPLC‐MS‐MS) using an atmos‐pheric pressure ionization (API) source and an ion spray (IS) interface for the specific direct detection of natural (progesterone and testosterone), and synthetic (17β19‐nortestosterone and me‐droxyprogesterone) hormone residues in bovine serum. 17‐Methyl‐testosterone was used as the internal standard. Analytes were extracted with acetate buffer, purified on C18 Solid Phase Extrac‐tion (SPE) cartridge and separated on a reverse phase C18 micro‐HPLC column (300 mm × 1 mm, 5 μm), using acetonitrile‐water, 80:20 (v/v) containing 2mM ammonium acetate as the mobile phase, at a flow rate of 10 μl/min. When anabolic hormones were ionized in the IS interface operating in the positive ion mode, only the protonated molecules, [M+H]+, were generated, without evidence of any fragmentation. These served as precursor ions for collision induced dissociation (CID) and Diagnostic daughter ions for each analyte were identified in order to carry out analysis by micro‐HPLC‐MS‐MS in the selected reaction monitoring (SRM) mode. For the analytes in question, the response of the mass detector was related linearly to the quantity of each analyte injected between 10 and 300 pg, in the SRM mode. The limit of detection, based on a 3:1 signal‐to‐noise ratio, is 6–7 pg for the hormones. Recoveries were higher than 83% for 17β‐19‐nortestosterone, testosterone, and 17‐methyltestosterone, and 72% for the medroxyprogesterone, and progesterone. The micro‐HPLC‐MS‐MS method for the determi‐nation of anabolic hormones in bovine blood requires no sample derivatization, minimal sample preparation, and provides a sensi‐tive, selective, rapid alternative to the existing purification, separa‐tion, and detection techniques. At present this very sensitive method is being successfully applied to measure bovine serum concentra‐tions of natural hormones, such as testosterone and progesterone, in order to then confirm any illegal administration of these sub‐stances.