Multidimensional LC

On-line heart-cut LC–GC and, more recently, comprehensive LC–GC (LC?GC) are very powerful analytical techniques because of the combination of the selectivity features of LC with the high efficiency of GC. This article presents an overview of the most recently used interfacing systems, as well as applications in the food analysis.

Analysis of natural compounds is becoming increasingly important. One thriving area is the evaluation and application of environmental biopolymers, such as humic substances (HSs) in various applications, including medicine, industry, agriculture and environmental protection.

Shimadzu Application Note

An optimization strategy to obtain the best possible performance in the shortest analysis time for comprehensive off-line 2D-LC.

Fully Automated Two-Dimensional LC Protein Separation using Monolithic Columns - Dionex Apps Note

HPLC 2008 was held in Baltimore in May. Columnist Ron Majors covers the highlights of this major symposium, held in the U.S. every two years.

Guest Editor Peter Schoenmakers provides an introduction to LCxLC, and then goes on to talk about peak capacity, sample dimensionality, phase orthogonality, and some of the successes of the technique and the obstacles yet to be overcome.

To characterize complex samples such as natural products or peptide digests, a single chromatographic dimension cannot completely separate and identify every single compound. For such cases, comprehensive two-dimensional liquid chromatography (LC x LC) is under rapid development.

This article describes the factors that affect the selection of columns for two-dimensional (2D) LCxLC separations.

Multidimensional liquid chromatography (MDLC) techniques are essential for the separation of highly complex proteomic samples. Advantages of off-line MDLC techniques over on-line approaches include high flexibility in choice of column dimensions and mobile-phase compositions, and the ability to reanalyse sample fractions. Here we present a fully automated off-line two-dimensional chromatographic approach for the analysis of proteomic samples using an UltiMate 3000 system optimized for proteomics MDLC.

This article describes the factors that affect the selection of columns for two-dimensional (2D) LCÃ-LC separations. The maximum increase in peak capacity compared with single-dimension (1D) separations is obtained by using "orthogonal" systems employing various combinations of separation mechanisms to provide as different separation selectivities as possible for the sample compounds in the first and in the second dimension systems. To obtain best results, matching the chemistry of the stationary phase, column dimensions and mobile phases in the first and in the second dimensions is essential for successful separations, especiall for comprehensive LCÃ-LC.

The authors address the specific separation problems of proteins and assess whether 2D liquid chromatography could possibly be considered as an alternative to traditional 2D gel electrophoresis in the future.

This application note compares a 1-D and 2-D HPLC separation coupled to MS for proteome analysis and finds that the 2-D method identifies 30% more proteins. (Grace Vydac)