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11.
Quantification of veterinary antibiotics (sulfonamides and trimethoprim) in animal manure by liquid chromatography-mass spectrometry 总被引:22,自引:0,他引:22
Haller MY Müller SR McArdell CS Alder AC Suter MJ 《Journal of chromatography. A》2002,952(1-2):111-120
A fast and cost effective method was developed to extract and quantify residues of veterinary antimicrobial agents (antibiotics) in animal manure by liquid-liquid extraction and liquid chromatography-mass spectrometry. The compounds investigated include six sulfonamides, one metabolite, and trimethoprim. The method was performed without sample clean up. Recoveries from spiked manure slurry samples (spike level = 1 mg/kg) were as follows: sulfaguanidine (52%), sulfadiazine (47%), sulfathiazole (64%), sulfamethazine (89%), its metabolite N4-acetyl-sulfamethazine (88%), sulfamethoxazole (84%), sulfadimethoxine (51%), and trimethoprim (64%). Relative standard deviations of the recoveries were less than 5% within the same day and less than 20% between days. The limit of quantification was below 0.1 mg/kg liquid manure slurry for all compounds and calibration curves obtained from extracts of spiked samples were linear up to a level of 5 mg/kg liquid manure, except for trimethoprim (0.01-0.5 mg/kg). Analysis of six grab samples taken in Switzerland from manure pits on farms where medicinal feed had been applied revealed total sulfonamide concentrations of up to 20 mg/kg liquid manure. 相似文献
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The fundamental bands of the CCl3 asymmetric deformation modes of selected isotopomers of chloroform (CHCl3) and freon-11 (CFCl3) have been measured in a static cell at ambient temperature using a laser-based source of tunable radiation in the terahertz region of the electromagnetic spectrum. The analysis of the rotational contours of the bands enabled the derivation of the fundamental frequencies with an accuracy of better than 3 GHz. 相似文献
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The similar electrophoretic mobilities and sizes of several of the phycobiliproteins, which are derived from the photosynthetic apparatus of cyanobacteria and eukaryotic algae, render their separation and quantitation a challenging problem. However, we have developed a suitable capillary electrophoresis (CE) method that employs a phytic acid-boric acid buffer and laser-induced fluorescence (LIF) detection with a single 594 nm He-Ne laser. This method takes advantage of the remarkably high quantum yields of these naturally fluorescent proteins, which can be attributed to their linear tetrapyrrole chromophores covalently bound to cysteinyl residues. As such, limits of detection of 1.18 x 10(-14), 5.26 x 10(-15), and 2.38 x 10(-15) mol/l were obtained for R-phycoerythrin, C-phycocyanin, and allophycocyanin proteins, respectively, with a linear dynamic range of eight orders of magnitude in each case. Unlike previously published CE-LIF methods, this work describes the separation of all three major classes of phycobiliproteins in under 5 min. Very good recoveries, ranging from 93.2 to 105.5%, were obtained for a standard mixture of the phycobiliproteins, based on seven-point calibration curves for both peak height and peak area. It is believed that this development will prove useful for the determination of phycobiliprotein content in naturally occurring cyanobacteria populations, thus providing a useful tool for understanding biological and chemical oceanographic processes. 相似文献
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Zapf A Jackstell R Rataboul F Riermeier T Monsees A Fuhrmann C Shaikh N Dingerdissen U Beller M 《Chemical communications (Cambridge, England)》2004,(1):38-39
A practical synthesis of a novel class of phosphine ligands, phosphino substituted N-aryl pyrroles (PAP ligands), has been developed. These ligands are applied in the palladium-catalyzed coupling of a variety of aryl and heteroaryl chlorides with phenylboronic acid showing exceedingly high turnover numbers at mild reaction temperatures and even at room temperature. 相似文献
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Nofal Ibrahim Jerome Thiebaud Christa Fittschen 《Journal of Molecular Spectroscopy》2007,242(1):64-69
In this paper we present measurements of the air-broadening coefficients of HO2 at room temperature in the 2ν1 band around 1.5 microns. The HO2 radicals were created by flash photolysis of SOCl2 in a flow of O2/CH3OH mixtures. To observe air-broadening, N2 (79%) and O2 (21%) were added using calibrated flow controllers and a total pressure controller. The total pressure was monitored in parallel using a capacitive pressure gauge. Air-broadening coefficients at 296 K were determined for 34 absorption lines between 6631 and 6671 cm−1. The air-broadening coefficients of HO2 show a rotational dependence (decreasing from about 0.14 cm−1/atm for N″ = 3 to about 0.09 cm−1/atm for N″ = 10). No evidence for collisional narrowing was observed. 相似文献
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Ming J. Lau Ming W. Lau Christa Gunawan Bruce E. Dale 《Applied biochemistry and biotechnology》2010,162(7):1847-1857
Empty palm fruit bunch fiber (EPFBF), a readily available cellulosic biomass from palm processing facilities, is investigated
as a potential carbohydrate source for cellulosic ethanol production. This feedstock was pretreated using ammonia fiber expansion
(AFEX) and enzymatically hydrolyzed. The best tested AFEX conditions were at 135 °C, 45 min retention time, water to dry biomass
loading of 1:1 (weight ratio), and ammonia to dry biomass loading of 1:1 (weight ratio). The particle size of the pretreated
biomass was reduced post-AFEX. The optimized enzyme formulation consists of Accellerase (84 μL/g biomass), Multifect Xylanase
(31 μL/g biomass), and Multifect Pectinase (24 μL/g biomass). This mixture achieved close to 90% of the total maximum yield
within 72 h of enzymatic hydrolysis. Fermentation on the water extract of this biomass affirms that nutrients solely from
the pretreated EPFBF can support yeast growth for complete glucose fermentation. These results suggest that AFEX-treated EPFBF
can be used for cellulosic biofuels production because biomass recalcitrance has been overcome without reducing the fermentability
of the pretreated materials. 相似文献
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