GCxGC Operational Principle
- GCxGC chromatography applies multiple GC columns (nonpolar and polar, and uncoated columns) connected in series. An uncoated column is normally installed inside a modulator.
- Another uncoated column might be used as an interface from the analytical columns to a detector such as mass spectrometer.
- Effluent from the first column is trapped in the modulator for very short time before being focused and injected into the second column .
- The repetitive trapping and injection cycles allow the GCxGC system to generate two-dimensional chromatograms using specialized software.
- The two-dimensional chromatogram indicates the boiling point and polarity on the respective axes.
Examples of GCxGC columns
Although we provide a generic configuration of GCxGC columns, most customers provide their own specifications. However, your specifications of GCxGC columns are confidential.
- 1st column: 15m x 0.25 mm x 0.25 um Rxi-1ms (non-polar)
- 2nd column: 2m x 0.1 mm (uncoated for modulator)
- 3rd column: 10m x 0.15 mm x0.15 um Stabilwax (polar column)
- 4th column: 1m x 0.1 mm (uncoated for detector interface)
What do we offer?
Customized GC columns service
- Please ship or drop off your GC columns to ALAC along with your payment.
- ALAC will configure your GC columns.
Customized GC Columns with Polar and Non-Polar Stationary Phases and Uncoated Columns
Our innovative technology will provide you excellent quality GCxGC columns.
- Please provide the specification for the GC columns, such as type of column, length, etc, to ALAC along with your payment.
- ALAC will produce GCxGC columns based on your specifications.
- ALAC will manufacture your columns within 3 working days and do leak testing with the GCxGC columns.
- ALAC normally will ship the order within a week.
Traditional GC Operation
- Normally one analytical column is used for one injector and one detector.
- Analytical column can be a capillary or packed column with a polar or non-polar stationary phase.
Example of GCxGC Columns
Picture of GCxGC Column Configuration
Challenges of GCxGC Columns
Connections of multiple columns in series is always a challenging project due to:
- Leaks if a press-fit union is used without properly bonding technique.
- Peak tailing especially for oxygenates and sulfurs when a metal union is used.
- Large dead volume causes peak broadening or changes of peak shape.
- Connections break apart due to poor technique.