Omni-Cell® System

A Universal Transmission Cell for the analysis of liquids and mulls in FT-IR or Dispersive Spectroscopy


Specac Omni-cell liquid transmission

The Omni-Cell® System is a low cost novel approach to the analysis of liquid samples in transmission spectroscopy – one cell is suitable for all applications. The cells are compatible with all FT-IR Spectrometers as well as older dispersive systems and can easily be configured for use as demountable liquid cells, permanently sealed liquid cells or as mull cells. 

Transmission is a well established technique for analyzing samples in the infrared. The choice of window material, pathlength and window configuration are determined by the sample and wavelength range of interest. Samples can be analyzed neat or diluted with an appropriate solvent. For quantitative analysis, the sample is often analyzed in a cell with a known pathlength. A guide to the selection of the correct pathlength for various concentrations is given below:


Solid samples can be analyzed using the mull technique. The solid is combined with a mulling agent such as Nujol or Fluorolube to form a mull which is analyzed between circular windows.

(All cells are shipped as a kit of parts and require assembly by the user)

Demountable Cell

This is a general-purpose cell for all liquids. It has the advantage of being easy to dismantle for cleaning, and for changing windows and spacers.omni-cell-demountable


  • General purpose
  • All liquids
  • Quantitative analysis

Sealed Cell

The window pair and spacer are amalgamated as an assembly. The advantages of this cell are constant pathlength for quantitative analysis and suitability for use omni-cell-sealedwith volatile liquids.


  • Volatile liquids
  • Quantitative applications
  • Low viscosity liquids


Mull Cell

The Mull Cell does not use the standard liquid filling ports. A suitable sample is placed between 2 circular windows, then squeezed together by tightening theomni-cell-mull

Omni-Cell® body parts. The advantage is that very viscous liquids, gels and pastes can easily be analyzed.


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


Liquid Omni-Cell® Volumes

(Rectangular windows – top drilled, bottom undrilled)

  • Mylar spacer 0.006 mm thick – 1.82 microliters
  • Mylar spacer 0.012 mm thick – 3.64 microliters
  • Mylar or lead spacer 0.025 mm thick – 7.5 microliters
  • PTFE or lead spacer 0.05 mm thick – 15.50 microliters
  • PTFE or lead spacer 0.10 mm thick – 30.00 microliters
  • PTFE or lead spacer 0.20 mm thick – 60.00 microliters
  • PTFE or lead spacer 0.50 mm thick – 150.00 microliters
  • PTFE or lead spacer 1.00 mm thick – 300.00 microliters

Demountable Liquid Omni-Cell® Window Pair dimensions: (Rectangular) 41mm x 23mm

Mull Omni-Cell® Window Pair dimension: (Circular) 25mm Dia

Available Window materials:

  • NaCl
  • KBr
  • CaF2
  • BaF2
  • ZnSe
  • KRS-5
  • CsI
  • CsBr
  • Silica (IR)
  • AgBr
  • Silicon
  • Polythene


Available Spacers:

  • 0.05mm PTFE Spacers
  • 0.10mm PTFE Spacers
  • 0.20mm PTFE Spacers
  • 0.50mm PTFE Spacers
  • 1.00mm PTFE Spacers
  • 0.025mm Lead Spacers
  • 0.05mm Lead Spacers
  • 0.10mm Lead Spacers
  • 0.20mm Lead Spacers
  • 0.50mm Lead Spacers
  • 1.00mm Lead Spacers
  • 0.006mm Mylar Spacers
  • 0.012mm Mylar Spacers
  • 0.025mm Mylar Spacers
  • Assorted PTFE Spacers