A laser-beam based optical sensor was also shown to be capable of rapidly detecting 45 E. coli cells in Nanopure water (Acharya et al., 2006), but the arrangement of the sensor elements (laser diode, photodiode, bandpass filter) for the consistent alignment of the light path and the correct data acquisition is much more labor intensive and technically demanding than the selective filtration system that utilizes the simple solution aspiration mechanism with the conventional filter.
Nanopure water