Sampling of Gases:

The gaseous samples are taken in approximately 10 cm long cuvettes having sodium chloride windows at either end as display in Figure (a). The cuvette is kept across the path of infrared beam. The path length of the cells could be simply varied over a long range. Within these specially designed cuvettes the internal surfaces are made reflective while the radiation could be made to travel by the sample several a times before coming out of it.

(a)                                                                             (b)

Figure: Sampling cuvettes for a) gaseous and b) liquid samples