Hydrophilic interaction chromatography has been applied for the separation of epirubicin and its analogues using high-purity silica column with aqueous-organic mobile phase. Parameters affecting the chromatographic behavior of the solutes such as organic modifier, buffer pH, ionic strength and sample size, have been investigated. Of utmost importance for successful separation of these analogues is the choice of organic modifier, since it impacts both the solvent selectivity and the ionization of silica silanols as well as buffer solution, and consequently the retention behavior of solutes. Acetonitrile was shown to offer superior separation of these analogues to methanol, isopropanol or tetrahydrofuran. Results of the effects of organic modifier, buffer pH and ion strength indicate that the retention mechanism is a mixed-mode of adsorption and ion exchange. In addition, an irreversible adsorption of these compounds was found on silica in the weakly acidic or neutral mobile phases, and the effect of various factors on irreversible adsorption was also preliminarily discussed. More significantly, these basic compounds have exhibited peaks with a slanted front and a sharp tail, a typical overloading peak profile belonging to the behavior of competitive anti-Langmuir isotherm by increasing the sample size at the experimental conditions.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.chroma.2004.04.033 | DOI Listing |
Nanoscale
January 2025
Department of Materials Science and Engineering, Chair for Surface Science and Corrosion (WW4-LKO), Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 7, 91058 Erlangen, Germany.
The photocatalytic degradation of unwanted organic species has been investigated for decades using modified and non-modified titania nanostructures. In the present study, we investigate the co-catalytic effect of single atoms (SAs) of Pt and Pt nanoparticles on titania substrates on the degradation of the two typical photodegradation model pollutants: Acid Orange 7 (AO7) and Rhodamine B (RhB). For this, we use highly defined sputter deposited anatase layers and load them with Pt SAs at different loading densities or alternatively with Pt nanoparticles.
View Article and Find Full Text PDFLangmuir
January 2025
Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran, Iran.
Carbon microspheres (CMSs) are recognized as highly effective microwave absorbers due to their exceptional wave absorption properties. In this study, 5,10,15,20-tetrakis(4-aminophenyl)porphyrin, a metamaterial, was chemically bonded to CMSs─considered a conjugated carbon structure─using a 1,3-dibromopropane linker to explore the synergistic properties and microwave absorption capabilities of the synthesized composite. The synthesized structures were characterized by using X-ray diffraction, FE-SEM, Fourier transform infrared, diffuse reflectance spectroscopy, and VNA analyses.
View Article and Find Full Text PDFInorg Chem
January 2025
Institute of Low Temperature and Structure Research, PAS, Okolna 2, 50-422 Wroclaw, Poland.
This paper discusses the origin of emission quenching in yttrium orthovanadate codoped with Eu and Sb ions. Highly crystalline yttrium orthovanadate nanoparticles with chemical composition YEuSbVO ( = 0-5.4 mol %, = 0-2.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P.R. China.
Plasmonic superlattices enable the precise manipulation of electromagnetic fields at the nanoscale. However, the optical properties of static lattices are dictated by their geometry and cannot be reconfigured. Here, we present a surface-interface engineered plasmonic superlattice with confined polyelectrolyte-functionalized metal-organic framework (MOF) hybrid layers to tune plasmon resonance for ultrafast chemical sensing.
View Article and Find Full Text PDFCommun Chem
January 2025
Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague 6, Prague, Czech Republic.
Protein-RNA interactions play important biological roles and hence reactive RNA probes for cross-linking with proteins are important tools in their identification and study. To this end, we designed and synthesized 5'-O-triphosphates bearing a reactive squaramate group attached to position 5 of cytidine or position 7 of 7-deazaadenosine and used them as substrates for polymerase synthesis of modified RNA. In vitro transcription with T7 RNA polymerase or primer extension using TGK polymerase was used for synthesis of squaramate-modified RNA probes which underwent covalent bioconjugations with amine-linked fluorophore and lysine-containing peptides and proteins including several viral RNA polymerases or HIV reverse transcriptase.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!