Optical spectroscopy sample cell

Abstract

A sample cell for use in spectroscopy includes two cell portions that are mutually adjustable to enable a user to vary the cross sectional geometry of sample cell flow path thereof between at least two discrete configurations or positions. In a first position, the flow path may be provided with a relatively small cross-sectional area to provide a relatively small pathlength and generate high velocity fluid flow therethrough. The small pathlength enables use of relatively small sample volumes and facilitates optical measurement of samples, such as blood, which have relatively high optical density, absorbance or light scattering properties. In a second position, the flow path provides a larger cross-section adapted to permit larger agglomerations or clots to pass through the flow path to facilitate cleaning of the sample cell. The cell portions are maintained in slidable engagement with one another so that the adjustability of the flow path is accomplished by sliding movement of the cell portions relative to one another. In one embodiment, the cell portions are engaged along generally planar mating surfaces and the adjustability is accomplished by sliding the mating surfaces relative to one another. In another embodiment, the mating surfaces are superposed in spaced relation to one another, and the adjustability is accomplished by varying the distance therebetween.