scholarly journals Improving chromatographic separation of polyolefins on porous graphitic carbon stationary phases: effects of adsorption promoting solvent and column length

RSC Advances ◽  
2020 ◽  
Vol 10 (31) ◽  
pp. 17942-17950 ◽  
Author(s):  
Anthony Ndiripo ◽  
Andreas Albrecht ◽  
Harald Pasch
Keyword(s):  
Chromatographic Separation ◽  
Mobile Phase ◽  
Stationary Phases ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Column Length

The chromatographic separation of complex polyolefins on porous graphitic carbon stationary phases is strongly influenced by the composition of the mobile phase.

scholarly journals Analysis of alkaloids from different chemical groups by different liquid chromatography methods

2012 ◽  
Vol 10 (3) ◽  
pp. 802-835 ◽  
Author(s):  
Anna Petruczynik
Keyword(s):  
Liquid Chromatography ◽  
Ion Exchange ◽  
Chromatographic Separation ◽  
Mobile Phase ◽  
Stationary Phases ◽  
Biologically Active ◽  
System Efficiency ◽  
Bonded Stationary Phases ◽  
Silica Alumina ◽  
Chemical Groups

AbstractAlkaloids are biologically active compounds widely used as pharmaceuticals and synthesised as secondary methabolites in plants. Many of these compounds are strongly toxic. Therefore, they are often subject of scientific interests and analysis. Since alkaloids — basic compounds appear in aqueous solutions as ionized and unionized forms, they are difficult for chromatographic separation for peak tailing, poor systems efficiency, poor separation and poor column-to-column reproducibility. For this reason it is necessity searching of more suitable chromatographic systems for analysis of the compounds. In this article we present an overview on the separation of selected alkaloids from different chemical groups by liquid chromatography thus indicating the range of useful methods now available for alkaloid analysis. Different selectivity, system efficiency and peaks shape may be achieved in different LC methods separations by use of alternative stationary phases: silica, alumina, chemically bonded stationary phases, cation exchange phases, or by varying nonaqueous or aqueous mobile phase (containing different modifier, different buffers at different pH, ion-pairing or silanol blocker reagents). Developments in TLC (NP and RP systems), HPLC (NP, RP, HILIC, ion-exchange) are presented and the advantages of each method for alkaloids analysis are discussed.

scholarly journals Attomol-level quantification of chemically modified ribonucleosides enabled by capillary porous graphitic carbon columns in nano LC-MS

2017 ◽  
Author(s):  
L. Peter Sarin ◽  
Sandra D. Kienast ◽  
Johannes Leufken ◽  
Robert L. Ross ◽  
Patrick A. Limbach ◽  
...  
Keyword(s):  
Biological Samples ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Detection Range ◽  
Rna Molecules ◽  
Chemically Modified ◽  
High Resolution Analysis ◽  
Resolution Analysis

ABSTRACTPost-transcriptional chemical modifications of (t)RNA molecules are crucial in fundamental biological processes, such as translation. Despite their biological importance and accumulating evidence linking them to various human diseases, technical challenges have limited the development of methods for reliable detection and accurate quantification of these modifications. Here, we present a sensitive capillary nanoflow liquid chromatography mass spectrometry (nLC-MS) pipeline for quantitative high-resolution analysis of ribonucleoside modifications from complex biological samples. We evaluated two porous graphitic carbon (PGC) materials as stationary phases for reversed-phase separation of ribonucleosides and found that both PGC matrices have excellent retention and separation characteristics, as well as the capability to separate structural isomers. Using PGC matrices in nLC-MS yielded excellent signal-to-noise ratios in a detection range spanning up to six orders of magnitude, allowing for the analysis of individual ribonucleosides down to attomol concentrations. Furthermore, normalizing the obtained signal intensities to a stable isotope labeled spike-in enabled direct comparison of ribonucleoside levels between different samples. In conclusion, capillary PGC columns coupled to nLC-MS constitute a powerful and sensitive tool for quantitative analysis of chemically modified ribonucleosides in complex biological samples. This setup will be invaluable for further unraveling the intriguing and multifaceted biological roles of RNA modifications.

Selective chromatographic separation of polycarbonate according to hydroxyl end-groups using a porous graphitic carbon column

2017 ◽  
Vol 1488 ◽  
pp. 77-84 ◽  
Author(s):  
N. Apel ◽  
E. Uliyanchenko ◽  
S. Moyses ◽  
S. Rommens ◽  
C. Wold ◽  
...  
Keyword(s):  
Chromatographic Separation ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
End Groups
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