Advanced white cell design for investigation of ethylene using a nondispersive infrared photometer

Ethylene (C2H4) is an important marker in the ripening process of climacteric fruit and is present down to ppb concentrations. Nondispersive infrared (NDIR) sensors are suitable for the selective detection of ethylene, provided they can reach better sensitivities. This can be achieved by increasing the optical path length, e.g. using long path cells. We present an advanced White cell design, which was optimized for implementation in NDIR sensors. The design offers an optical path of 4 m, an entrance aperture of up to 5x5 mm2 and a numerical aperture of 0.126. The implementation of the cell in a photometer setup for ethylene yielded a noise equivalent concentration of 860 ppb (1 s) C2H4 in nitrogen (N2).