Does the OD 600 method take place linearly on the BioPhotometer?
This measuring method is principally non-linear, when one observes the absorption curve over wide OD ranges and dilutions. The values are dependent on both the organism (size, shape) and the device (light path geometry, ratio of measured stray light radiation). A correct procedure includes the generation of a calibration graph for each organism and device by determining the actual number of cells under a microscope. When the curve shape is known it is then possible to measure in ranges that are almost linear. Applications on the topic of the dependency of OD values on the organism and device are listed on www.biophotometer.info. Just click on “More information”.
