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Application of a mixed-mode solid-phase extraction and cleanup procedure for LC/MS determination of thiabendazole and carbendazim in apple juice 总被引:2,自引:0,他引:2
Recently, a mixed-mode solid-phase extraction (SPE) procedure was developed for rapid extraction and cleanup for determination of the fungicides thiabendazole and carbendazim in various fruit juices. This paper reports the application of that sample preparation procedure to the liquid chromatographic/mass spectrometric determination of these fungicides in apple juice with detection by positive electrospray ionization mass spectrometry (ESI/MS). Response was linear for sample concentrations from 2 to 500 microg/L (ppb). Recoveries averaged 74% (9% RSD) for carbendazim and 93% (9% RSD) for thiabendazole. After SPE cleanup, no matrix supression was observed for the ESI+ response for either compound studied. The method was applied to the analysis of incurred residues in 4 store-bought apple juices; carbendazim levels ranged from 10 to 70 microg/L and thiabendazole levels ranged from less than 2 to 130 microg/L. 相似文献
24.
Angang Song Igal Levine Roel van de Krol Thomas Dittrich Sean P. Berglund 《Chemical science》2020,11(41):11195
p-Type CuBi2O4 is considered a promising metal oxide semiconductor for large-scale, economic solar water splitting due to the optimal band structure and low-cost fabrication. The main challenge in utilizing CuBi2O4 as a photoelectrode for water splitting, is that it must be protected from photo-corrosion in aqueous solutions, an inherent problem for Cu-based metal oxide photoelectrodes. In this work, several buffer layers (CdS, BiVO4, and Ga2O3) were tested between CuBi2O4 and conformal TiO2 as the protection layer. RuOx was used as the co-catalyst for hydrogen evolution. Factors that limit the photoelectrochemical performance of the CuBi2O4/TiO2/RuOx, CuBi2O4/CdS/TiO2/RuOx, CuBi2O4/BiVO4/TiO2/RuOx and CuBi2O4/Ga2O3/TiO2/RuOx heterojunction photoelectrodes were revealed by comparing photocurrents, band offsets, and directed charge transfer measured by modulated surface photovoltage spectroscopy. For CuBi2O4/Ga2O3/TiO2/RuOx photoelectrodes, barriers for charge transfer strongly limited the performance. In CuBi2O4/CdS/TiO2/RuOx, the absence of hole traps resulted in a relatively high photocurrent density and faradaic efficiency for hydrogen evolution despite the presence of pronounced deep defect states at the CuBi2O4/CdS interface. Hole trapping limited the performance moderately in CuBi2O4/BiVO4/TiO2/RuOx and strongly in CuBi2O4/TiO2/RuOx photoelectrodes. For the first time, our results show that hole trapping is a key factor that must be addressed to optimize the performance of CuBi2O4-based heterojunction photoelectrodes.CdS, BiVO4, and Ga2O3 buffer layers were tested between CuBi2O4 and TiO2 in heterojunction photoelectrodes. Photoelectrochemical analysis and modulated surface photovoltage spectroscopy revealed that interface hole traps impacted device performance. 相似文献
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M. Marder E. Katz D. S. Davis P. S. Panjutin W. N. Tischkowa Office Central de Chauffe Rationelle R. Koetschau J. I. Fogelsson F. Chierer J. G. Ssemenido B. B. Krol W. P. Nikolskaja M. Richter A. Balada A. K. Tschertawskich H. Levin A. Baader H. Steinbrecher und H. Kühne 《Fresenius' Journal of Analytical Chemistry》1938,115(5-6):232-239
Ohne Zusammenfassung 相似文献
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M. Marder E. Katz D. S. Davis P. S. Panjutin W. N. Tischkowa R. Koetschau J. I. Fogelsson F. Chierer J. G. Ssemenido B. B. Krol W. P. Nikolskaja M. Richter A. Balada A. K. Tschertawskich H. Levin A. Baader H. Steinbrecher H. Kühne Office Central de Chauffe Rationelle 《Analytical and bioanalytical chemistry》1938,115(5-6):232-239
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The VO3?4 and Eu3+ luminescence in compounds with ordered β-K2SO4 structure is reported. The ratio of the Eu3+ and vandate emission intensity depends on the excitation energy. 相似文献
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The results of the Monte Carlo simulation of the LORD experiment are presented for two types of antenna systems with various parameters. The effect of possible polarization mismatch and galactic noise “percolation” are taken into consideration. 相似文献
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The amino acid selenocysteine represents the major biological form of selenium. Both the synthesis of selenocysteine and its co-translational incorporation into selenoproteins in response to an in-frame UGA codon, require a complex molecular machinery. To decode the UGA Sec codon in eubacteria, this machinery comprises the tRNASec, the specialized elongation factor SelB and the SECIS hairpin in the selenoprotein mRNAs. SelB conveys the Sec-tRNASec to the A site of the ribosome through binding to the SECIS mRNA hairpin adjacent to the UGA Sec codon. SelB is thus a bifunctional factor, carrying functional homology to elongation factor EF-Tu in its N-terminal domain and SECIS RNA binding activity via its C-terminal extension. In archaea and eukaryotes, selenocysteine incorporation exhibits a higher degree of complexity because the SECIS hairpin is localized in the 3' untranslated region of the mRNA. In the last couple of years, remarkable progress has been made toward understanding the underlying mechanism in mammals. Indeed, the discovery of the SECIS RNA binding protein SBP2, which is not a translation factor, paved the way for the subsequent isolation of mSelB/EFSec, the mammalian homolog of SelB. In contrast to the eubacterial SelB, the specialized elongation factor mSelB/EFSec the SECIS RNA binding function. The role is carried out by SBP2 that also forms a protein-protein complex with mSelB/EFSec. As a consequence, an important difference between the eubacterial and eukaryal selenoprotein synthesis machineries is that the functions of SelB are divided into two proteins in eukaryotes. Obviously, selenoprotein synthesis represents a higher degree of complexity than anticipated, and more needs to be discovered in eukaryotes. In this review, we will focus on the structural and functional aspects of the SelB and SBP2 factors in selenoprotein synthesis. 相似文献