Effect of pre- and post-column band broadening on the performance of high-speed chromatography columns under isocratic and gradient conditions

Peak deconvolution to correctly assess the band broadening of chromatographic columns

“…(14) in ref. [31], it can be verified that the entrance length needed to achieve the long time dispersion limit in an open tubular capillary (where the dispersion varies linearly with the length L) is only satisfied when:…”

“…Each data point is the average of five runs (for interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article). In all literature where the variance method is used [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], it is implicitly assumed that a chromatographic column behaves as a good radial mixer, which has the following important consequence. If used with a column in between them, the pre-tubing and postcolumn tubing dispersion can be expected to be independent of each other, as the column lets the fluid elements "forget" about the history they experienced in the pre-column tubing before they enter the post-column tubing.…”

“…This also puts a serious strain on the ability to measure the "columnonly" efficiency of these columns [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], especially when using weakly retained components. This is most regrettable, for it can be inferred that it are especially these peaks that are most sensitive to the hydrodynamic quality of the packing, which is precisely one of the main parameters one is after when trying to determine the column-only efficiency [9][10][11][12][13][14][15][16]32,33].…”

“…subtraction method, owing its popularity to the fact that it is based on a simple subtraction [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] …”

Repeatability of gradient ultrahigh pressure liquid chromatography–tandem mass spectrometry methods in instrument-controlled thermal environments

“…Even in unstable thermal conditions like these, the impact on quantifying the analytes of interest is limited (although it may not be for larger biomolecules [57]) and suggests that fast UHPLC runs at pressures up to 1500 bar should be feasible (within the limits of MS scan rate to ensure sufficient ion counts). A follow-up study on how the UHPLC-MS/MS neurotransmitter analysis method might be affected by column dimensions [58] and extra-column volumes [59,60] at these high speeds is ongoing.…”