An improved on-line metal chelate affinity chromatography-high-performance liquid chromatography (MCAC-HPLC) method for the determination of tetracycline antibiotics in animal tissues and egg has been developed. Extraction was carried out with ethyl acetate. The extract was then evaporated to dryness and reconstituted in methanol prior to on-line MCAC clean-up and HPLC-UV determination. Recoveries of tetracycline, oxytetracycline, demeclocycline and chlortetracycline in the range 42% to 101% were obtained from egg, poultry, fish and venison tissues spiked at 25 micrograms kg-1. Limits of detection less than 10 microgram kg-1 were estimated for all four analytes. This method has higher throughput, higher recovery and lower limits of detection than a previously reported on-line MCAC-HPLC method which involved aqueous extraction and solid-phase extraction clean-up.
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http://dx.doi.org/10.1016/s0021-9673(97)01290-9 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States.
A significant challenge in commercializing electrochemical CO reduction (COR) is achieving catalyst durability. In this study, online inductively coupled mass spectrometry (ICP-MS) was used to investigate catalyst degradation via nanoparticle detachment and/or dissolution into metal ions under COR operating conditions in 0.1 M KHCO.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, PR China. Electronic address:
Catalytic oxidation of formaldehyde (HCHO) is a highly effective method for indoor HCHO removal. However, many aspects of the catalytic mechanism remain unclear, making the optimization of catalysts largely empirical. Herein, we report a coupled experimental and computational study of Pt/TiO catalysts, with special focus on the functional roles of surface oxygen vacancies and hydroxyl groups in the catalytic oxidation of HCHO.
View Article and Find Full Text PDFNat Commun
January 2025
ICGM, Univ. Montpellier, CNRS, ENSCM, 34095, Montpellier, France.
The long-term stability of Pt-based catalysts is critical to the reliability of proton exchange membrane fuel cells (PEMFCs), and receives constant attention. However, the current knowledge of Pt oxidation is restricted to unrealistic PEMFC cathode environment or operation, which questions its practical relevance. Herein, Pt oxidation is investigated directly in a PEMFC with stroboscopic operando high energy X-ray scattering.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Shenzhen Research Institute of Xiamen University, Shenzhen 518000, China; College of the Environment and Ecology, Xiamen University, Xiamen 361005, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen 361005, China. Electronic address:
Due to the distinct difference in chemical properties, analysis of organic pollutants and heavy metals generally employs different sample preparation and measurement techniques, resulting in low analytical efficiency and high cost. To this end, a strategy for the co-extraction and then simultaneous quantification of organic pollutants and heavy metals was proposed by the on-line hyphenation of magnetic field-assisted in-tube solid phase microextraction (MA/IT-SPME) and HPLC technique. Simultaneous analysis of triazoles and chromium species were adopted as paradigm to demonstrate the feasibility of the proposed strategy.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia.
In situ measurements of the chemical identity and quantity of anode gases during electrochemical measurements and rare earth (RE) electrolysis from fluoride-based molten salts composed of different kinds of rare earth oxides (REOs) were performed using FTIR spectrometry. Linear sweep voltammetry (LSV) was carried out to characterize oxidation processes and determine the anodic effect from NdF + PrF + LiF + REO melt. RE complex formation and subsequent reactions on the GC anode surface were discussed to understand the formation pathways of CO/CO and perfluorocarbon gases (PFC), mainly CF and CF.
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