We desired to evaluate the chromatographic selectivity for peptides of silica-based RP high-performance liquid chromatography stationary phases with various modifications (polar embedding and polar endcapping on C(18) columns; ether-linked phenyl column with polar endcapping) compared with n-alkyl (C(18), C(8)) and aromatic phenylhexyl columns. Thus, we have designed and synthesized two series of synthetic peptide standards with the sequence Gly-Gly-Leu-Gly-Gly-Ala-Leu-Gly-X-Leu-Lys-Lys-amide, where the N-terminal either contains a free α-amino group (AmC series) or is N(α)-acetylated (AcC series) and where position X is substituted by Gly, Ala, Val, Ile, Phe or Tyr. These represent series of peptides with single substitutions of n-alkyl (Gly
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http://dx.doi.org/10.1002/jssc.201000518 DOI Listing Publication Analysis
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J Chromatogr A
December 2024
Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
We performed multiscale simulations of analyte sorption and diffusion in hierarchical porosity models of monolithic silica columns for reversed-phase liquid chromatography to investigate how the mean mesopore size of the chromatographic bed and the analyte-specific interaction with the chromatographic interface influence the analyte diffusivity at various length scales. The reproduced experimental conditions comprised the retention of six analyte compounds of low to moderate solute polarity on a silica-based, endcapped, C stationary phase with water‒acetonitrile and water-methanol mobile phases whose elution strength was varied via the volumetric solvent ratio. Detailed information about the analyte-specific interfacial dynamics received from molecular dynamics simulations was incorporated through appropriate linker schemes into Brownian dynamics diffusion simulations in three hierarchical porosity models received from physical reconstructions of silica monoliths with a mean macropore size of 1.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2025
Pharmacoanalytical Shared Resource, Comprehensive Cancer Center The Ohio State University, 460 W. 12th Ave, Columbus, OH 43210, USA; Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, 496 W. 12th Ave, Columbus, OH 43210, USA. Electronic address:
An isotope-dilution bioanalytical assay for abemaciclib and its metabolites in combination with olaparib was developed and validated in human plasma K2 EDTA. For the quantitative assay, human plasma samples (or human plasma QC samples) were spiked with internal standard solution before a simple protein precipitation with methanol. The extract was injected onto a liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrument where it was chromatographically separated by a polar end-capped reversed phase column and guard using gradient elution with water and methanol both modified with 0.
View Article and Find Full Text PDFThiophene-containing heteroarenes are one of the most well-known classes of π-conjugated building blocks for photoactive molecules. Isomeric naphthodithiophenes (NDTs) are at the forefront of this research area due to their straightforward synthesis and derivatization. Notably, NDT geometries that are bent - such as naphtho[2,1-:3,4-']dithiophene (α-NDT) and naphtho[1,2-:4,3-']dithiophene (β-NDT) - are seldom employed as photoactive small molecules.
View Article and Find Full Text PDFMar Drugs
June 2024
Key Laboratory of Cultivation and High-Value Utilization of Marine Organisms in Fujian Province, National Research and Development Center for Marine Fish Processing (Xiamen), Xiamen 361013, China.
Omega-3 fatty acids are in high demand due to their efficacy in treating hypertriglyceridemia and preventing cardiovascular diseases. However, the growth of the industry is hampered by low purity and insufficient productivity. This study aims to develop an efficient RP-MPLC purification method for omega-3 fatty acid ethyl esters with high purity and capacity.
View Article and Find Full Text PDFJ Chromatogr A
March 2024
Waters Corporation, Instrument/Core Research/Fundamental, 34 Maple Street, Milford, MA, 01757, USA.
Chromatographers often employ fully aqueous mobile phases to retain highly polar compounds in reversed-phase liquid chromatography (RPLC). However, when the flow rate is interrupted, either accidentally or intentionally, a substantial loss in retention occurs due to the spontaneous dewetting of water from the hydrophobic surface of conventional RPLC-C particles. Previous studies have shown that maintaining a low C surface coverage (approximately 1.
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