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See detailDetermination of As in Industrial Wastewater by Laser-Induced Breakdown Spectroscopy
Lin, Zhaoxiang; Chang, Liang; Li, Jie ULg et al

in Spectroscopy and Spectral Analysis (2009), 29(6), 1675-1677

The wastewater from industrial smelting process contains heavy metals such as arsenic(As)that produce serious environmental pollution and cause actual harm to the health of people. It is necessary to ... [more ▼]

The wastewater from industrial smelting process contains heavy metals such as arsenic(As)that produce serious environmental pollution and cause actual harm to the health of people. It is necessary to control the pollution at the source and achieve a real-time and online monitoring.The 1aser-induced breakdown spectroscopy(LIBS)iS a new elemental analysis technique,and has the advantage of rapid detection.An LIBs setup has been established.The Nd:YAG Iaser beam is focused onto the sample,then the plasmas are produced.The emission spectra of plasmas are dispersed by an Echelle spectrograph and detected by an intensified charge-coupled device(ICCD).Experiments have been carried out on the industrial wastewarer collected from the scene.The spectral lines of As element were obtained.The calibration curve of the line intensities versus the concentrations of the As element was acquired by the experiment.The calibration curve can be used for the quantitative analysis of arsenic element with an unknown concentration in the industrial wastewater.The results showed that the LIBS technique can be applied in the rapid detection of As element in industrial wastewater,and has wide range of applications [less ▲]

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See detailDetermination of Benzodiazepines by Micellar Electrokinetic Chromatography
Bechet, I.; Fillet, Marianne ULg; Hubert, Philippe ULg et al

in Electrophoresis (1994), 15(10), 1316-21

A method for the separation and determination of benzodiazepines by micellar electrokinetic chromatography (MEKC) has been developed. Separation buffers consisted of aqueous solutions of glycine and ... [more ▼]

A method for the separation and determination of benzodiazepines by micellar electrokinetic chromatography (MEKC) has been developed. Separation buffers consisted of aqueous solutions of glycine and triethanolamine (pH 9.0), containing sodium dodecyl sulfate (SDS) as surfactant and methanol as organic modifier. The effect of the concentration of SDS, methanol, glycine and triethanolamine on migration times and resolution was studied. Ten benzodiazepines were baseline separated at a 25 mM SDS concentration and 20% v/v methanol in a 75 mM glycine-250 mM triethanolamine buffer. Under these conditions, the within-day reproducibilities were 0.3-0.5% for migration times and 1.7-1.9% for peak areas at a concentration of 10 micrograms/mL. The limits of detection and quantification for oxazepam were 0.2 and 0.7 micrograms/mL, respectively, using an injection time of 5 s. [less ▲]

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See detailDetermination of binary polymorphic mixtures of fluconazole using near infrared spectroscopy and X-ray powder diffraction: A comparative study based on the pre-validation stage results
Ziemons, Eric ULg; Bourichi, H.; Mantanus, Jérôme ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 55

The aim of the present study was to develop near infrared (NIR) and X-ray powder diffraction methods (XRPD) able to determine pure crystalline form II of fluconazole in a binary polymorphic mixtures ... [more ▼]

The aim of the present study was to develop near infrared (NIR) and X-ray powder diffraction methods (XRPD) able to determine pure crystalline form II of fluconazole in a binary polymorphic mixtures containing form II and III. In order to give a first performance estimation of both methods, these latters were pre-validated using accuracy profiles, a statistical approach based on β-expectation tolerance intervals. Both methods showed a good trueness, precision and accuracy and their β-expectation tolerance intervals were fully included within the acceptance limits. The comparative study was carried out using statistical analysis based on the work of Bland and Altman. A good agreement between the two methods was demonstrated indicating the interchangeability of NIR method with XRPD method. [less ▲]

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See detailDetermination of blood concentration levels of psychotrope medications in Rwandan patients
Hahirwa, Innocent; DENOOZ, Raphael ULg; Karangwa, Charles et al

in Acta Clinica Belgica (2015)

OBJECTIVES: In Rwanda, no therapeutic monitoring of psychotropic drugs is done. This results in difficult treatment optimisation and exposition to a high risk of toxicity and drug ineffectiveness for ... [more ▼]

OBJECTIVES: In Rwanda, no therapeutic monitoring of psychotropic drugs is done. This results in difficult treatment optimisation and exposition to a high risk of toxicity and drug ineffectiveness for patients under treatment. This study aimed to determine blood concentration levels of psychotropic drugs in Rwandan patients and identify problems associated with the lack of therapeutic drug monitoring (TDM) of these drugs. METHODS: The analysis was performed on 1 ml of serum sample using prazepam as internal standard. Regarding the step of sample preparation, we used a liquid-liquid extraction with a mixture of organic solvents: diethyl ether/dichloromethane/hexane/n-amyl alcohol (50/30/20/0.5:V/V). A Waters Alliance 2695 was used for analysis. The chromatography was run on a Symmetry C8 column and as mobile phase acetonitrile and phosphate buffer (pH 3.8) were used. RESULTS: Concerning the results, serum samples from 128 patients were analysed. Twenty-one different psychotropic drugs belonging to various pharmacological classes were detected and quantified. Analytical results were put into three categories based upon therapeutic reference ranges (TRR) of various drugs: subtherapeutic, therapeutic and supratherapeutic. For a total of 237 analyses, results within TRR represented 46% while 47 and 8% of results were, respectively, below and above TRR. CONCLUSION: It was therefore concluded that patients under psychotropic treatment in Rwanda are exposed to both the risk of drug ineffectiveness and the risk of toxicity (54%) with only 46% of results within the TRR. Consequently, TDM is needed to optimise psychotropic treatment in Rwandan patients. [less ▲]

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See detailDetermination of cardiac performance in healthy dogs during maximal inotropic stimulation with dobutamine.
Mc Entee, Kathleen ULg; Clercx, Cécile ULg; Pypendop, Bruno et al

in Proceedings of the 4th Annual Congress of the ESVIM (1994)

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See detailDetermination of charge carrier transport properties in organic devices by admittance spectroscopy : application to hole mobility in α-NPD
Nguyen, Ngoc Duy ULg; Schmeits, Marcel; Loebl, Hans-Peter

in Physical Review. B : Condensed Matter (2007), 75

Hole mobility in N,N′-diphenyl-N,N′-bis(1-naphtylphenyl)-1,1′-biphenyl-4,4′-diamine (α-NPD) is evaluated by electrical characterization in the ac regime. The frequency-dependent complex admittance and ... [more ▼]

Hole mobility in N,N′-diphenyl-N,N′-bis(1-naphtylphenyl)-1,1′-biphenyl-4,4′-diamine (α-NPD) is evaluated by electrical characterization in the ac regime. The frequency-dependent complex admittance and impedance of the structure consisting of the organic layer, grown by thermal evaporation, sandwiched by indium tin oxide and aluminum electrodes, are measured as functions of the applied dc voltage. The capacitance response shows negative values for frequencies below a characteristic value depending on the bias and ranging from 0.1 Hz up to 20 Hz. It increases with the modulation frequency and reaches a peak, the magnitude and position of which are functions of the applied voltage. For higher frequencies, a minimum can be observed before the capacitance increases again up to a constant value. A final decreasing occurs at frequency of 4×106 Hz. The analysis of the experimental data is performed by a detailed theoretical study of the steady-state and small-signal electrical characteristics of the device. Numerical calculations are based on the solution of the basic semiconductor equations for the system consisting of two electrodes connected by the semiconducting channel formed by the organic layer. The description explicitly includes a continuous distribution of trap density of states and a field-dependent carrier mobility. The spatially dependent charge carrier and occupied trap concentrations, as well as the various components to the total current density, are obtained for the dc and ac regimes and are analyzed for given bias and frequency. Based on a formalism used in the study of inorganic semiconductors, the results of the simulation show that the inductive contribution to the capacitance response originates from the modulation of the hole concentration in the organic material, leading to the corresponding carrier transit time. Moreover, the low-frequency behavior of the capacitance curves could be explained by the presence of a band of defect states which modifies the charge distribution within the organic layer and the injection of electrons from the cathode. We show that the latter contribution is also responsible for the negative values of the capacitance measured below 10 Hz. Good agreement is observed between the experimental and theoretical electrical characteristics, in particular for the differential susceptance results and the subsequent hole mobility values. Our approach can be a useful contribution for the methodology of obtaining mobilities from admittance measurements as it allows one to clarify the physical origin of the measured frequency-dependent capacitance and to check for the experimental procedure. This work finally leads to the formulation of the conditions under which small-signal ac measurements can be used to determine carrier mobility in organic devices. [less ▲]

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See detailDetermination of chloramphenicol in honey, shrimp and poultry meat with liquid chromatography-mass spectrometry. Validation of the method according to Commission Decision 2002/657/EC
Douny, Caroline ULg; Widart, Joëlle ULg; De Pauw, Edwin ULg et al

in Food Analytical Methods (2013), 6(5), 1458-1465

Chloramphenicol (CAP) is an antibiotic used for the treatment of bacterial infections in human and veterinary medicine. The use of CAP was prohibited in the European Union in 1994. Control laboratories ... [more ▼]

Chloramphenicol (CAP) is an antibiotic used for the treatment of bacterial infections in human and veterinary medicine. The use of CAP was prohibited in the European Union in 1994. Control laboratories are required to use suitably validated analytical methods to check sample compliance with the regulation. A quantitative method based on liquid chromatography coupled to isotopic dilution tandem mass spectrometry (LC–IDMS/MS) was developed for the determination of chloramphenicol in honey, shrimp and poultry meat. The experimental protocol consisted of a liquid-liquid extraction with ethyl acetate. Separation and detection were realized respectively by a 2690 Waters HPLC (Milford, MA, USA) and a Micromass Triple Quadrupole mass spectrometer (Micromass, Manchester, UK), equipped with an Electrospray source. The effects of mobile phase additives on the response of LC/ESI/MS were examined. Two different HPLC columns were tested: the X-Terra from Waters and the Alltima HP C18 HL from Alltech (Deerfield, IL, USA). A validation of the method was conducted according to the EU criteria for the analysis of chloramphenicol in foods. The decision limits (CCα) were 0.04, 0.03, 0.07 µg kg-1 and the detection capabilities (CCβ) were 0.05, 0.04, 0.08 µg kg-1 for honey, shrimp and poultry meat respectively. Those values are below the minimum required performance limit (MRPL) set at 0.3 µg kg-1 by the EU and 0.1 µg kg-1 by Belgium. Our protocol has the advantage to propose a unique extraction method working as well for honey, shrimp and poultry meat, contrary to similar published methods in which a different extraction method is used for each type of matrix. [less ▲]

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See detailDetermination of CK-MB mass in clinical practice
Chapelle, Jean-Paul ULg

Conference (1997, February 03)

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See detailDetermination of COBALT in patients with metal hip prosthesis
MISTRETTA, Virginie ULg; Charlier, Corinne ULg

Poster (2014, October 18)

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See detailDetermination of COF2 vertical distributions above Jungfraujoch by FTIR and multi-spectra fitting
Duchatelet, Pierre ULg; Mahieu, Emmanuel ULg; Demoulin, Philippe ULg et al

Poster (2007, April)

The major sources of fluorine in the stratosphere are CFC-11 and CFC-12. Photolysis of these compounds leads to release of chlorine atoms, while the fluorine is, in a first step, present in the form of ... [more ▼]

The major sources of fluorine in the stratosphere are CFC-11 and CFC-12. Photolysis of these compounds leads to release of chlorine atoms, while the fluorine is, in a first step, present in the form of carbonyl compounds like COClF and COF2. Their further photolysis liberates fluorine atoms, which are quickly converted to HF. Given its long life time, COF2 is the second stratospheric fluorine reservoir. The first COF2 vertical distributions were derived from occultation measurements performed by the ATMOS instrument during the SPACELAB-3 Space Shuttle mission in 1985. The Canadian FTIR spectrometer ACE-FTS, onboard the SCISAT-1 satellite, is the first instrument since the last ATMOS flight in 1994, to record COF2 vertical profiles from space. All these observations show that, at mean latitudes, COF2 concentration is maximum between 30 and 35 km. Several COF2 IR absorption lines located either in the so-called InSb (1-5 µm) and MCT (2-16 µm) spectral ranges can be used to determine its total column from ground-based FTIR observations. In this context, several studies concerning the evolution of COF2 total column above various stations were published during the nineties. At this time, no study concerning the inversion of COF2 vertical distributions from ground-based FTIR spectra has been published. This report deals with the feasibility of such inversions, using, simultaneously, via the SFIT-2 v3.91 algorithm, a multi-microwindows and a multi-spectra fitting procedure. The multi-spectra method consists of combining several FTIR observations, recorded during the same day, to increase the information content. A selection of microwindows in InSb and MCT ranges, a complete discussion about the data characterization (e.g. information content) and typical examples of COF2 retrieved profiles from high resolution solar spectra recorded with the University of Liège Jungfraujoch FTS will be revealed. [less ▲]

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See detailDetermination of critical current in bulk high temperature superconductors by magnetic flux profile measuring methods
Vanderbemden, Philippe ULg

Doctoral thesis (1999)

In this thesis, the emphasis is placed on determining the critical current density in bulk high-temperature superconductors by magnetic flux profile measuring methods. The thesis involves three different ... [more ▼]

In this thesis, the emphasis is placed on determining the critical current density in bulk high-temperature superconductors by magnetic flux profile measuring methods. The thesis involves three different aspects : a brief theoretical investigation of the flux profile methods, the practical realization of an experimental set-up intended for measuring such profiles and a discussion of flux profile measurements in several bulk high-temperature superconductors. [less ▲]

Detailed reference viewed: 54 (9 ULg)