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P Sanders - One of the best experts on this subject based on the ideXlab platform.
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confirmatory analysis for spiramycin residue in bovine muscle by liquid chromatography Particle Beam mass spectrometry
Journal of Mass Spectrometry, 1994Co-Authors: P Sanders, B DelepineAbstract:To ensure that residues of veterinary drugs, above their respective maximum residue limits, do not reach the human food supply, European Community regulations specify requirements for detection, quantification and confirmation analytical methods and control procedures. The European Community member states base meat controls on these protocols. A liquid chromatographic/mass spectrometric analysis of spiramycin in calf muscle is presented as a confirmatory method for this compound. A Particle Beam interface was used, with negative ion chemical ionization mass spectrometry, using methane as the reagent gas. Samples (2 g muscle were prepared by liquid/liquid extraction followed by solid-phase extraction clean-up. On-line liquid chromatography/mass spectrometry of extracts was carried out on a C-18 bonded silica column. The specificity required for a regulatory confirmation procedure was achieved by monitoring five fragment ions with m/z 304, 330, 475, 683 and 684. Variation of the relative ion abundances was less than 20% at the maximum limit of residue, 50 micrograms kg-1. The method specificity was tested for three related compounds: neospiramycin, erythromycin and tylosin. The detection limit based on ion chromatogram peaks areas obtained with control samples was determined to be 20 micrograms kg-1.
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identification of tylosin in bovine muscle at the maximum residue limit level by liquid chromatography mass spectrometry using a Particle Beam interface
Analyst, 1994Co-Authors: B Delepine, D Hurtaud, P SandersAbstract:A Particle Beam liquid chromatography–mass spectrometric method is presented as a confirmatory technique for analysis of tylosin residues in bovine muscle. After chloroform extraction and a diol solid-phase extraction clean-up, on-line liquid chromatography–mass spectrometry (LC–MS) of extracts is carried out on an RP-18 bonded silica column. The analyte is introduced into the ion source by a Particle Beam interface and identified by negative chemical ionization with selective ion monitoring. The tylosin molecular ion is obtained with this ionization mode. The response of the ion chromatogram peak areas is linear for the three levels of spiked muscle analysed (0.5, 1 and 2 maximum residue limit). Under these LC–MS conditions, other macrolide antibiotics such as spiramycin and erythromycin do not interfere with tylosin.
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Particle Beam liquid chromatography mass spectrometry method with negative ion chemical ionization for the confirmation of oxacillin cloxacillin and dicloxacillin residues in bovine muscle
Analyst, 1994Co-Authors: D Hurtaud, B Delepine, P SandersAbstract:To ensure human food safety, the European Union has defined maximum residue limits (MRLs) for veterinary drug residues in food products. Analytical methods need to be developed to confirm the presence of drugs at the MRL level. A method using Particle Beam liquid chromatography–mass spectrometry was developed for the confirmation of oxacillin, cloxacillin and dicloxacillin in bovine muscle at the maximum residue limit of 300 µg kg–1. Beta-lactams were extracted from tissues with ethyl acetate under slightly acidic conditions and separated on a C18 bonded silica column with a methanol–aqueous formic acid (2%) solution–acetonitrile mobile phase. Negative ion chemical ionization with methane as the reagent gas was used to identify the compounds. The specificity required for a regulatory confirmation procedure was achieved by monitoring five fragment ions for each compound (selected ion monitoring mode): m/z 183, 198, 213, 214 and 241 for oxacillin; m/z 196, 248, 250, 275 and 277 for cloxacillin; m/z 165, 230, 232, 274 and 276 for dicloxacillin.
Herbert J Tobias - One of the best experts on this subject based on the ideXlab platform.
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supramicrometer Particle shadowgraph imaging in the ionization region of a single Particle aerosol mass spectrometer
Journal of Aerosol Science, 2008Co-Authors: George R Farquar, Herbert J Tobias, Matthias Frank, Paul T Steele, Erica L Mcjimpsey, Carlito B Lebrilla, Eric E Gard, Keith R Coffee, Vincent J RiotAbstract:Abstract An in situ method to image individual aerosol Particles upon desorption/ionization in a single Particle aerosol mass spectrometer using shadowgraph imaging is presented and applied directly to determine a 2D spatial distribution of 5.0 μ m Particles. This new technique is complementary to previously reported methods for the determination of focused Particle Beam profiles and has several advantages, including a very low Particle concentration requirement and the ability to collect the image of an individual Particle with a correlated mass spectrum. Images are presented for 1.3, 2.1, 3.0, and 5.0 μ m polystyrene latex spheres. Particle Beam profiles are presented in the directions perpendicular and parallel to the Particle Beam axis. These results are qualitatively compared to those of a complementary Particle collection method (dusting) used at Lawrence Livermore National Laboratory to characterize aerosol Beam focusing.
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chemical analysis of diesel engine nanoParticles using a nano dma thermal desorption Particle Beam mass spectrometer
Environmental Science & Technology, 2001Co-Authors: Herbert J Tobias, Darrick D Zarling, Robert Waytulonis, Peter H. Mcmurry, Derek E Beving, Hiromu Sakurai, Paul Ziemann, David B. KittelsonAbstract:Diesel engines are known to emit high number concentrations of nanoParticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoParticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoParticles (mass median diameter ∼25−60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption Particle Beam mass spectrometry. Mass spectra were used to identify and quantify nanoParticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoParticle mass. The volatility of the organic fraction of the aerosol increases as the engi...
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real time chemical analysis of organic aerosols using a thermal desorption Particle Beam mass spectrometer
Aerosol Science and Technology, 2000Co-Authors: Herbert J Tobias, Peter M Kooiman, Kenneth S Docherty, Paul ZiemannAbstract:An instrument has been developed for real-time, quantitative chemical analys is of organic Particles in laboratory environments. In this apparatus, which we call a Thermal Desorption Particle Beam Mass Spectrometer (TDPBMS), Particles are sampled into a differentially-pumped vacuum chamber, focused into a narrow, low-divergence Particle Beam using aerodynamic lenses, and then transported into a high-vacuum region where they impact on a heated surface, evaporate, and the vapor is mass analyzed in a quadrupole mass spectrometer. The average composition of a continuous stream of Particles is thus measured in real time, and size-dependent composition can be obtained by passing the incoming aerosol through a differential mobility analyzer. The TDPBMS can analyze multi component organic Particles in the 0.02-0.5mu m size range for compound concentrations 0.1-1mu g m3 without Particle matrix effects. By using careful calibration techniques that account for Particle shape and transport efficiency, the particulate...
Paul Ziemann - One of the best experts on this subject based on the ideXlab platform.
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chemical analysis of diesel engine nanoParticles using a nano dma thermal desorption Particle Beam mass spectrometer
Environmental Science & Technology, 2001Co-Authors: Herbert J Tobias, Darrick D Zarling, Robert Waytulonis, Peter H. Mcmurry, Derek E Beving, Hiromu Sakurai, Paul Ziemann, David B. KittelsonAbstract:Diesel engines are known to emit high number concentrations of nanoParticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoParticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoParticles (mass median diameter ∼25−60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption Particle Beam mass spectrometry. Mass spectra were used to identify and quantify nanoParticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoParticle mass. The volatility of the organic fraction of the aerosol increases as the engi...
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real time chemical analysis of organic aerosols using a thermal desorption Particle Beam mass spectrometer
Aerosol Science and Technology, 2000Co-Authors: Herbert J Tobias, Peter M Kooiman, Kenneth S Docherty, Paul ZiemannAbstract:An instrument has been developed for real-time, quantitative chemical analys is of organic Particles in laboratory environments. In this apparatus, which we call a Thermal Desorption Particle Beam Mass Spectrometer (TDPBMS), Particles are sampled into a differentially-pumped vacuum chamber, focused into a narrow, low-divergence Particle Beam using aerodynamic lenses, and then transported into a high-vacuum region where they impact on a heated surface, evaporate, and the vapor is mass analyzed in a quadrupole mass spectrometer. The average composition of a continuous stream of Particles is thus measured in real time, and size-dependent composition can be obtained by passing the incoming aerosol through a differential mobility analyzer. The TDPBMS can analyze multi component organic Particles in the 0.02-0.5mu m size range for compound concentrations 0.1-1mu g m3 without Particle matrix effects. By using careful calibration techniques that account for Particle shape and transport efficiency, the particulate...
B Delepine - One of the best experts on this subject based on the ideXlab platform.
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confirmatory analysis for spiramycin residue in bovine muscle by liquid chromatography Particle Beam mass spectrometry
Journal of Mass Spectrometry, 1994Co-Authors: P Sanders, B DelepineAbstract:To ensure that residues of veterinary drugs, above their respective maximum residue limits, do not reach the human food supply, European Community regulations specify requirements for detection, quantification and confirmation analytical methods and control procedures. The European Community member states base meat controls on these protocols. A liquid chromatographic/mass spectrometric analysis of spiramycin in calf muscle is presented as a confirmatory method for this compound. A Particle Beam interface was used, with negative ion chemical ionization mass spectrometry, using methane as the reagent gas. Samples (2 g muscle were prepared by liquid/liquid extraction followed by solid-phase extraction clean-up. On-line liquid chromatography/mass spectrometry of extracts was carried out on a C-18 bonded silica column. The specificity required for a regulatory confirmation procedure was achieved by monitoring five fragment ions with m/z 304, 330, 475, 683 and 684. Variation of the relative ion abundances was less than 20% at the maximum limit of residue, 50 micrograms kg-1. The method specificity was tested for three related compounds: neospiramycin, erythromycin and tylosin. The detection limit based on ion chromatogram peaks areas obtained with control samples was determined to be 20 micrograms kg-1.
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identification of tylosin in bovine muscle at the maximum residue limit level by liquid chromatography mass spectrometry using a Particle Beam interface
Analyst, 1994Co-Authors: B Delepine, D Hurtaud, P SandersAbstract:A Particle Beam liquid chromatography–mass spectrometric method is presented as a confirmatory technique for analysis of tylosin residues in bovine muscle. After chloroform extraction and a diol solid-phase extraction clean-up, on-line liquid chromatography–mass spectrometry (LC–MS) of extracts is carried out on an RP-18 bonded silica column. The analyte is introduced into the ion source by a Particle Beam interface and identified by negative chemical ionization with selective ion monitoring. The tylosin molecular ion is obtained with this ionization mode. The response of the ion chromatogram peak areas is linear for the three levels of spiked muscle analysed (0.5, 1 and 2 maximum residue limit). Under these LC–MS conditions, other macrolide antibiotics such as spiramycin and erythromycin do not interfere with tylosin.
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Particle Beam liquid chromatography mass spectrometry method with negative ion chemical ionization for the confirmation of oxacillin cloxacillin and dicloxacillin residues in bovine muscle
Analyst, 1994Co-Authors: D Hurtaud, B Delepine, P SandersAbstract:To ensure human food safety, the European Union has defined maximum residue limits (MRLs) for veterinary drug residues in food products. Analytical methods need to be developed to confirm the presence of drugs at the MRL level. A method using Particle Beam liquid chromatography–mass spectrometry was developed for the confirmation of oxacillin, cloxacillin and dicloxacillin in bovine muscle at the maximum residue limit of 300 µg kg–1. Beta-lactams were extracted from tissues with ethyl acetate under slightly acidic conditions and separated on a C18 bonded silica column with a methanol–aqueous formic acid (2%) solution–acetonitrile mobile phase. Negative ion chemical ionization with methane as the reagent gas was used to identify the compounds. The specificity required for a regulatory confirmation procedure was achieved by monitoring five fragment ions for each compound (selected ion monitoring mode): m/z 183, 198, 213, 214 and 241 for oxacillin; m/z 196, 248, 250, 275 and 277 for cloxacillin; m/z 165, 230, 232, 274 and 276 for dicloxacillin.
Ramanujan Jagannathan - One of the best experts on this subject based on the ideXlab platform.
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quantum mechanics of charged Particle Beam transport through magnetic lenses
Physical Review E, 1995Co-Authors: Sameen Ahmed Khan, Ramanujan JagannathanAbstract:The quantum theory of charged-Particle Beam transport through a magnetic lens system with a straight optic axis, at the level of single-Particle dynamics and disregarding spin (or, when nonzero, assuming it to be an independent spectator degree of freedom), is presented, based on the Schroedinger and Klein-Gordon equations in a form suitable for analyzing the paraxial and aberration aspects in a systematic way using a Lie algebraic approach. In the classical limit, the well known Lie algebraic treatment of the corresponding classical theory is obtained. As examples, quadrupole and axially symmetric magnetic lenses are considered. An extension of the theory to the cases of electrostatic and other electromagnetic lens systems is outlined. This work is complementary to an already known similar approach to the spinor electron optics based on the Dirac equation and provides the corresponding framework when the optics of charged Particles, with or without spin, is described with scalar wave functions in the nonrelativistic and relativistic situations.