The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Wolfgang Thormann - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar Electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar Electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar Electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar Electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar Electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar Electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar Electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
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determination of substituted purines in body fluids by micellar Electrokinetic Capillary Chromatography with direct sample injection
Journal of Chromatography A, 1992Co-Authors: Wolfgang Thormann, Andrea Minger, Sarah Molteni, Jitka Caslavska, Petr GebauerAbstract:Many substituted purines (theobromine, caffeine, paraxanthine, theophylline and uric acid, as well as other methylated xanthines and uric acids) can easily be separated and analysed in one run using micellar Electrokinetic Capillary Chromatography with a boratephosphate buffer containing 75 mM sodium dodecyl sulphate (pH approximately 9). Serum, saliva and urine samples collected after the self-administration of caffeine and serum samples from patients receiving theophylline or caffeine pharmacotherapy were screened for substituted purines. The data presented show the ease of using on-column multi-wavelength detection for investigating the feasibility of direct sample application, the characterization of sample pretreatment procedures and peak confirmation by comparing absorption spectra. It is shown that the determination of purines in serum and saliva samples, including therapeutic concentrations of caffeine and theophylline, can be accomplished without any sample pretreatment, whereas sample extraction is required for the determination of purines in urine. Quantitative data for the determination of micromolar amounts of theophylline (samples from adult patients) and caffeine (samples from infants born prematurely) in serum samples compared well with data obtained by non-isotopic immunoassays. Micellar Electrokinetic Capillary Chromatography with the direct injection of serum or saliva samples requires only microlitre volumes of sample and several different compounds can be determined within a few minutes.
Parham Sendi - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar Electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar Electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar Electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar Electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar Electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar Electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar Electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Nela Sestakova - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar Electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar Electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar Electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar Electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar Electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar Electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar Electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Regula Theurillat - One of the best experts on this subject based on the ideXlab platform.
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monitoring of cefepime in urine by micellar Electrokinetic Capillary Chromatography with ultraviolet detection and liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Mirjam Kummer, Nela Sestakova, Regula Theurillat, Uyen Huynhdo, Andrea Endimiani, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in urine by micellar Electrokinetic Capillary Chromatography with UV detection and liquid Chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime. Cefepime monitoring by micellar Electrokinetic Capillary Chromatography in samples from patients taking multiple drugs were prone to interferences, whereas liquid Chromatography coupled to mass spectrometry provided clean chromatograms and thus selective detection of cefepime in all samples. The latter assay was used to measure urinary cefepime in a prospective pilot study and to assess cefepime stability in urines at 25, 4, -20 and -70°C. The data suggest that urinary cefepime is stable for at least 72 h at all tested temperatures.
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monitoring of cefepime in human serum and plasma by micellar Electrokinetic Capillary Chromatography improvement of sample preparation and validation by liquid Chromatography coupled to mass spectrometry
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Nela Sestakova, Regula Theurillat, Parham Sendi, Wolfgang ThormannAbstract:Cefepime monitoring in deproteinized human serum and plasma by micellar Electrokinetic Capillary Chromatography and liquid Chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar Electrokinetic Capillary Chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid Chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar Electrokinetic Capillary Chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid Chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar Electrokinetic Capillary Chromatography could thereby be validated. This article is protected by copyright. All rights reserved
Alessandra Bonetti - One of the best experts on this subject based on the ideXlab platform.
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Separation and detection of herbicides in water by micellar Electrokinetic Capillary Chromatography.
Journal of chromatography. B Biomedical applications, 1994Co-Authors: Giovanni Dinelli, Alessandra Bonetti, Pietro Catizone, Guido C. GallettiAbstract:Abstract The herbicides linuron, metolachlor, atrazine and metsulfuron were analysed using micellar Electrokinetic Capillary Chromatography (MECC) after a 1000-fold concentration step by solid-phase extraction (SPE). Recoveries ranged from 80 to 92%, depending on the concentration and the number of active substances in the sample. Furthermore, the hydrolysis products of metsulfuron were analysed by MECC and by gas Chromatography—mass spectrometry (GC—MS). Representative MECC and GC—MS profiles are shown and the structures of the hydrolysis products are proposed on the basis of their chromatographic and mass spectra features. A tentative pathway for the degradation of metsulfuron is proposed.
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micellar Electrokinetic Capillary Chromatography analysis of water soluble vitamins and multi vitamin integrators
Electrophoresis, 1994Co-Authors: Giovanni Dinelli, Alessandra BonettiAbstract:Micellar Electrokinetic Capillary Chromatography (MECC) was applied to the determination of water-soluble vitamins (WSV) in pharmaceutical preparations. The analytical procedure employed in the WSV separation by MECC showed a satisfactory average column efficiency (195,000 N) and resolution (more than 100 theoretical peaks separable). The mean reproducibility in the retention time of consecutive and day-to-day runs was 1.1% and 5.1%, respectively. Analyses were performed after extraction of active ingredients by solid phase extraction. Recoveries (92-103%) and relative variation coefficients (less than 5%) confirmed the potential of MECC in the field of pharmaceutical analysis.