At the heart of the Pearl™ accessory is Specac's innovative Oyster™ cell assembly, which forms a fixed pathlength without spacers or fasteners. The top part of the cell can be simply lifted out of the way to allow for fast and easy application and cleaning of the sample. For more volatile samples, there is an injection access port in the top of the Oyster™ cell so that the assembly does not have to be fully opened. The sample can be viewed through the two windows, allowing the user to ensure that no bubbles have been trapped.
The Oyster™ cell can be cleaned very easily and quickly using tissue and an appropriate solvent. The Pearl™ has been designed to provide a more accurate pathlength than can be achieved using a traditional liquid transmission accessory, with pathlengths repeatable to significantly better than 1 μm thanks to the Oyster™ sample holder.
Oyster™ cells have the unique feature of being offered with either parallel mounted windows, or windows with a slight wedge angle to remove troublesome fringing patterns. Pearl™ can be fitted with ZnSe or CaF2 Oyster™ cell assemblies which can be interchanged in seconds. Oyster™ cells are available in six pathlengths from 25 to 1000 μm.
The Oyster™ cell mechanism is so easy to use that it makes the Pearl™ accessory suitable for handling highly viscous samples such as oils and greases.