Using a Universal Transmission Cell to Analyze Mulls and Liquids in Dispersive Spectroscopy or FTIR

Any liquid sample can be analyzed via IR transmission using just one cell with the Omni-CeII^TM System.

Omni-CeII^TM systems can be used with any type of FT-IR spectrometer and also with older systems, which use dispersive methods. The cells can be also used as a stand alone liquid cell, for mull cell experiments, or as a fully sealed liquid cell.

Omni-Cell^TM makes the execution of transmission experiments, an established and reliable technique for IR analysis, as simple as possible. Sample analysis can be carried out with the sample either in a pure or solvent diluted form.

A variety of different cell pathlengths, and window configurations and materials can be chosen depending on the requirements of a particular experiment. The below table shows the optimum pathlength for different analytical concentrations.

Solid samples can also be analyzed in the liquid phase using a mull technique, where the solid is mixed with Nujol (a mulling agent) to form a mull (suspension). As with other experiments, the mull is then analyzed through the circular windows of the Omni Cell^TM.

Features

• Quick to assemble and change windows
• FITR and Dispersive compatibility
• Low cost and reliable
• Windows and Spacers compatible with older cells
• Quick release clamping mechanism
• Wide choice of window materials

Applications

Mull Cells

• High viscosity liquids
• Gels and pastes
• Oils and greases
• Solids suspended as mulls

Sealed Cells

• Low viscosity liquids
• Quantitative applications
• Volatile liquids

Demountable Cells

• All liquids
• General purpose
• Quantitative analysis

Variations of the Omni Cell^TM

Demountable Cell

The demountable cell is the generic version of the Omni Cell^TM. It is designed for the analysis of all liquids, with quantitative results, and is easily removed from the analysis apparatus, making cleaning and changing of spacers and windows as simple as possible.

Sealed Cell

In sealed cells, the windows and spacer are built into the cell, i.e. they cannot be adjusted. While this reduces the flexibility of the cell it allows use with volatile liquids and provides a consistent pathlength for accurate quantitative analysis.

The design of the sealed cell makes it perfect for the analysis of low viscosity and volatile liquids.

Mull Cell

The Mull Cell is designed for use in Mull experiments, i.e. where a solid suspension is used. For this reason the cell does not use conventional liquid ports and instead the sample is sandwiched between the cell’s two windows.

This set up allows a variety of ‘difficult’ samples to be analyzed via transmission IR. Examples would include highly viscous liquids and solid-liquids such as pastes and gels, as well as oils and greases, and (as the name suggests) solids suspended in mulls.

This information has been sourced, reviewed and adapted from materials provided by Specac.

For more information on this source, please visit Specac.