The ASD12-N probe is specifically engineered for use in laboratory fermenters. The seal-less sapphire window design eliminates crevices and gaps to ensures the highest level of sterility. All wetted parts are electropolished steel. The ASD12-N is autoclavable and mounts conveniently through any headplate with a PG13.5 threaded port.
The ASD12-N is available in three different insertion depths with either 5 or 10 mm OPLs (optical path length = distance between the windows). Shorter optical path lengths are typically used for dense cell cultures such as bacterial and yeast cultures. Longer OPLs are used for less dense cell cultures e.g. mammalian cells and dissolution / precipitation / crystallization reactions.
A precisely defined and constant LED light beam penetrates the process medium. ASD12-N, ASD19-N and ASD25-N use light from 840 nm to 910 nm (NIR). The attenuation of the light intensity, caused by absorption by dissolved substances and undissolved material is detected by a hermetically sealed photodiode.