Sequential multimodal elution for pseudomultidimensional liquid chromatography on a single column

Little, Edward L.; Jeansonne, Mark S.; Foley, Joe P.

doi:10.1021/ac00001a007

Cited by 32 publications

(11 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The concept of D C can also be applied to the sequential elution style of separation [13] or to D C columns in series, but its usage here is specific to the (integral) number of columns in a multidimensional experiment. In the context of multidimensional chromatography, D C ≤ s , where s is Giddings’ sample dimensionality [14].…”

Section: Mathematical Developmentmentioning

confidence: 99%

Orthogonality measurements for multidimensional chromatography in three and higher dimensional separations

Schure¹,

Davis

2017

Journal of Chromatography A

View full text Add to dashboard Cite

Orthogonality metrics (OMs) for three and higher dimensional separations are proposed as extensions of previously developed OMs, which were used to evaluate the zone utilization of two-dimensional (2D) separations. These OMs include correlation coefficients, dimensionality, information theory metrics and convex-hull metrics. In a number of these cases, lower dimensional subspace metrics exist and can be readily calculated. The metrics are used to interpret previously generated experimental data. The experimental datasets are derived from Gilar’s peptide data, now modified to be three dimensional (3D), and a comprehensive 3D chromatogram from Moore and Jorgenson. The Moore and Jorgenson chromatogram, which has 25 identifiable 3D volume elements or peaks, displayed good orthogonality values over all dimensions. However, OMs based on discretization of the 3D space changed substantially with changes in binning parameters. This example highlights the importance in higher dimensions of having an abundant number of retention times as data points, especially for methods that use discretization. The Gilar data, which in a previous study produced 21 2D datasets by the pairing of 7 one-dimensional separations, was reinterpreted to produce 35 3D datasets. These datasets show a number of interesting properties, one of which is that geometric and harmonic means of lower dimensional subspace (i.e., 2D) OMs correlate well with the higher dimensional (i.e., 3D) OMs. The space utilization of the Gilar 3D datasets was ranked using OMs, with the retention times of the datasets having the largest and smallest OMs presented as graphs. A discussion concerning the orthogonality of higher dimensional techniques is given with emphasis on molecular diversity in chromatographic separations. In the information theory work, an inconsistency is found in previous studies of orthogonality using the 2D metric often identified as %O. A new choice of metric is proposed, extended to higher dimensions, characterized by mixes of ordered and random retention times, and applied to the experimental datasets. In 2D, the new metric always equals or exceeds the original one. However, results from both the original and new methods are given.

show abstract

Section: Mathematical Developmentmentioning

confidence: 99%

Orthogonality measurements for multidimensional chromatography in three and higher dimensional separations

Schure¹,

Davis

2017

Journal of Chromatography A

View full text Add to dashboard Cite

show abstract

“…It has been termed pseudo-MDLC when the same sample is sequentially eluted with different conditions. Such methods have only additive P c (Little et al, 1991) and the entire sample is not subjected to all separation modes; thus, true comprehensive MDLC criteria cannot be met. Certain types of multi-modal separation are truly multidimensional.…”

Section: Planarmentioning

confidence: 99%

Comprehensive multi‐dimensional liquid chromatographic separation in biomedical and pharmaceutical analysis: a review

Dixon

Pitfield

Perrett

2006

Biomedical Chromatography

View full text Add to dashboard Cite

‘Multi‐dimensional’ liquid separations have a history almost as long as chromatography. In multi‐dimensional chromatography the sample is subjected to more than one separation mechanism; each mechanism is considered an independent separation dimension. The separations can be carried out either offline via fraction collection, or directly coupled online. Early multi‐dimensional separations using combinations of paper chromatography, electrophoresis and gels, in both planar and columnar modes are reviewed. Developments in HPLC have increased the number of measurable analytes in ever more complex matrices, and this has led to the concept of ‘global metabolite profiling’. This review focuses on the theory and practice of modern ‘comprehensive’ multi‐dimensional liquid chromatography when applied to biomedical and pharmaceutical analysis. Copyright © 2006 John Wiley & Sons, Ltd.

show abstract

“…Selection of the mobile phase suitable for each dimension is crucial in all LC6LC 2-D systems, except for SEC, to get maximum use of the space available for 2-D separations by designing comprehensive separation systems. By carefully selected combinations of two or more elution modes with different mobile phases (such as sequential solvent and pH gradients), to elute only certain classes of compounds in each mode, "pseudo-multidimensional" separations can be accomplished on a single column, even though with a lower peak capacity than with true multidimensional separations [100]. When selecting mobile phase for each dimension, compatibility of the mobile phase transferred from the first dimension with the separation in the second dimension should be considered.…”

Section: Stationary and Mobile Phase Compatibility For 2-d Lcmentioning

confidence: 99%

Column selectivity for two‐dimensional liquid chromatography

Jandera¹

2006

J of Separation Science

View full text Add to dashboard Cite

Selectivity of phase system is of primary concern when designing a 2-D separation, as it affects the 2-D system orthogonality and consequently the peak capacity controlling the number of peaks that can be separated in the available 2-D retention space limited by the time of analysis. Possibilities for characterization of LC phase system selectivity with respect to different polar and nonpolar structural units are compared, with special attention to multidimensional samples with various types of repeat groups, such as homopolymers, (co)polymers, fatty acid esters with various acyl lengths and number and position of double bonds, etc. Possibilities of the 2-D LC separations of these and other sample types, including pharmaceuticals, natural phenolic compounds, biopolymers, etc., using various combinations of separation modes are reviewed. Rules for design of comprehensive 2-D LC x LC systems are discussed, with respect to mobile phase compatibility in the two systems and modulation techniques suppressing band broadening connected with the sample fraction transfer from the first to the second dimension. Pitfalls connected with online connection of normal-phase and RP LC systems and their possible practical solutions are addressed and illustrated by practical examples.

show abstract

Sequential multimodal elution for pseudomultidimensional liquid chromatography on a single column

Cited by 32 publications

References 59 publications

Orthogonality measurements for multidimensional chromatography in three and higher dimensional separations

Orthogonality measurements for multidimensional chromatography in three and higher dimensional separations

Comprehensive multi‐dimensional liquid chromatographic separation in biomedical and pharmaceutical analysis: a review

Column selectivity for two‐dimensional liquid chromatography

Contact Info

Product

Resources

About