Two-dimensional chromatography

GCxGC-TOFMS Analytical Dept Chemical Faculty GUT Gdansk

Two-dimensional chromatography (2D chromatography) is an advanced form of chromatography that involves the separation of complex mixtures by passing them through two different chromatographic systems. This technique enhances the resolution and separation efficiency compared to one-dimensional chromatography.

Principles

Two-dimensional chromatography operates by first separating the sample using one chromatographic method, then transferring the separated components to a second chromatographic system with a different separation mechanism. This orthogonal approach allows for the separation of compounds that may co-elute in a single-dimensional system.

Techniques

There are several techniques used in two-dimensional chromatography, including:

• Two-dimensional gas chromatography (GC×GC)
• Two-dimensional liquid chromatography (LC×LC)
• Two-dimensional thin-layer chromatography (2D-TLC)

Two-dimensional gas chromatography (GC×GC)

In GC×GC, the sample is first separated on a primary column, typically a non-polar column. The effluent from the primary column is then introduced into a secondary column, usually a polar column, for further separation. This technique is particularly useful for the analysis of complex mixtures such as petroleum products and essential oils.

Two-dimensional liquid chromatography (LC×LC)

LC×LC involves the use of two liquid chromatography columns with different stationary phases. The first dimension often employs a reversed-phase column, while the second dimension may use a normal-phase or ion-exchange column. This method is widely used in the analysis of proteomics, metabolomics, and pharmaceuticals.

Two-dimensional thin-layer chromatography (2D-TLC)

In 2D-TLC, the sample is first separated on a thin-layer chromatography plate in one direction. After the first separation, the plate is rotated 90 degrees, and a second separation is performed using a different solvent system. This technique is useful for the analysis of complex mixtures in natural products and food chemistry.

Applications

Two-dimensional chromatography is used in various fields, including:

• Environmental analysis
• Pharmaceutical analysis
• Food and beverage analysis
• Proteomics
• Metabolomics

Advantages

The main advantages of two-dimensional chromatography include:

• Enhanced resolution and separation efficiency
• Ability to separate complex mixtures
• Improved identification and quantification of components

Limitations

Despite its advantages, two-dimensional chromatography has some limitations:

• Increased complexity and cost of instrumentation
• Longer analysis times
• Requirement for advanced data analysis techniques

Related Pages

• Chromatography
• Gas chromatography
• Liquid chromatography
• Thin-layer chromatography
• Proteomics
• Metabolomics