An un-derivatized 1.7 microm ethylene bridged hybrid (BEH) particle was evaluated for its utility in retaining polar species in hydrophilic interaction chromatography (HILIC), and was compared to a 3 microm un-derivatized silica material. Retentivity as a function of mobile phase pH, polar modifier and ACN content was examined. Also, the efficiency of the two particle substrates was compared by plotting HETP vs. linear velocity. Improved chemical resistance of the un-derivatized BEH particle was compared to un-derivatized silica at pH 5, demonstrating no performance deterioration over the course of 2000 injections for the BEH particle, while the silica particle deteriorated rapidly after 800 injections. Lastly, ESI-MS sensitivity as a function of particle size and separation mode was demonstrated. A 2.2 to 4.7-times higher ESI-MS response was observed on the 1.7 microm particle compared to the 3 microm particle, whereas a 5.6 to 8.8-times higher ESI-MS response was observed using HILIC as when compared to traditional RP chromatography.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/jssc.200700673 | DOI Listing |
J Chromatogr A
October 2023
Section of Drug Abuse Research, Department of Forensic Sciences, Division of Laboratory Medicine, Oslo University Hospital, P.O. Box 4950 Nydalen, N-0424 Oslo, Norway. Electronic address:
Alcohol consumption is associated with a wide risk of different diseases, injury and death, and has significant social and economic consequences worldwide. Phosphatidylethanol (PEth) is a group of promising direct alcohol biomarkers, with a significantly longer half-life in blood than ethanol, which can be measured to predict different drinking patterns, such as heavy- and social drinking. This study aimed to develop and validate an accurate and precise LC-MS/MS method for the determination of six PEth homologues in whole blood with minimal interference from unwanted phospholipids.
View Article and Find Full Text PDFChemosphere
November 2024
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
The occurrence and spatio-temporal distribution of atmospheric novel brominated flame retardants (NBFRs) were studied across five sampling sites in the Beijing-Tianjin-Hebei (BTH) region over a whole year. By collecting samples (gas and particle) with a high-volume active air sampler (HV-AAS), nine NBFRs were analyzed and the sum concentrations ranged from 1.65 to 344 pg/m, with the highest value found in the urban sampling site in Shijiazhuang City.
View Article and Find Full Text PDFAnal Chem
October 2024
Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany.
The accurate liquid chromatography-tandem mass spectrometry analysis of phosphorylated isomers from glycolysis and pentose phosphate pathways is a challenging analytical problem in metabolomics due to extraction problems from the biological matrix, adherence to stainless steel surfaces leading to tailing in LC, and incomplete separation of hexose and pentose phosphate isomers. In this study, we present a targeted HILIC-ESI-MS/MS method based on a BEH amide fully porous 1.7 μm particle column with an inert surface coating of column hardware and multiple reaction monitoring (MRM) acquisition fully covering the glycolysis and pentose phosphate pathway metabolites.
View Article and Find Full Text PDFJ Chromatogr A
November 2024
Waters Corporation, Core Research/Fundamental, Milford, MA, 01757, USA. Electronic address:
Slalom chromatography (SC) re-emerged in 2024 due to the availability of low adsorption ultra-high pressure liquid chromatography (UHPLC) packed columns/instruments and large modalities being investigated in the context of cell and gene therapies. The physico-chemical principles of SC retention combined with hydrodynamic chromatography (HDC) exclusion have been recently reported. In SC, DNA macromolecules are retarded because: (1) they can be stretched to lengths comparable to the particle diameter, and (2) their elastic relaxation time is long enough to maintain them in non-equilibrium extended conformations under regular UHPLC shear flow conditions.
View Article and Find Full Text PDFJ Chromatogr A
October 2024
Department of Chemical and Biological Engineering, Princeton University, 41 Olden Street, Princeton, NJ, 08544, USA. Electronic address:
Despite decades of research and development, the optimal efficiency of slurry-packed HPLC columns is still hindered by inherent long-range flow heterogeneity from the wall to the central bulk region of these columns. Here, we show an example of how this issue can be addressed through the straightforward addition of a semidilute amount (500 ppm) of a large, flexible, synthetic polymer (18 MDa partially hydrolyzed polyacrylamide, HPAM) to the mobile phase (1% NaCl aqueous solution, hereafter referred to as "brine") during operation of a 4.6 mm × 300 mm column packed with 10μm BEH 125 Å particles.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!